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Fibeglass boat and repair maintenance.

1. 410 Microlight A very low density filler for creating a light easily worked fairing com pound 410 spreads smoothly and sands very easily when cured Not recommended under dark colored paint or on other surfaces subject to high temperatures Cures to a light tan color See Appendix A for additional filler selection information Filler Selection Guide Figure 9 2 Suit ability of WEST SYSTEM fillers for various applica tions ADHESIVE FILLERS FAIRING FILLERS USES Highest density 4 Lowest density Resin Hardener mixture thickened with a Filler Highest strength Easiest Sanding Use description desired characteristics 404 406 403 405 407 410 High Density Colloidal Silica Microfibers Filleting Blend Low Density Microlight Bonding Hardware lIncrease fastener interface and hardware load capability maximum strength khkk kkk tok lafal to create a structural gap filer swrengthygap fing Hee xix xk and create a structural brace sinoothness strength A tock Ak etek kk Laminating Bond layers of wood strips veneers re ikk rower am P planks sheets and cores gap filling strength Fairing Fill low areas voids with an easily shaped and sanded surface filler sandability gap filling Akk tok tok Filler suitability Xxxx excellent k very good good fair no stars not recommended Use higher strength fillers when bonding higher density materials such as hardwoods or metal
2. Clamp the section in position Clean up excess epoxy before it cures Remove clamps after ep oxy cures thoroughly Replace the fiberglass skin as described in Section 3 4 1 3 4 Replacing stringers 1 Completely replacing a damaged stringer is often easier than replacing a section For example engine stringers commonly run from the transom to a bulkhead They may not run the entire length of the boat Complete replacement of the damaged stringer may be much easier than at tempting to replace a section of it Stringers can also be added to under engineered panels to im prove stiffness Replace stringers as follows Mark the location of the stringer before you remove it It is often critical that the stringer gets replaced in exactly the same position it was previously located Locate reference marks far enough away from the repair area so they will not be disturbed when you prep the area Remove the stringer and core Use a grinder to cut the tabbing at the core hull joint Do not cut into the hull laminate Save any large pieces of core you remove if they can be used as pattern to help fit the new core Measure the thickness of the fiberglass skin so you can duplicate it Repairing Stringers and Floor 14 3 Using the same species of wood as the existing core fit a new piece of core material to fit the size and shape of the core in the removed stringer See section 3 4 1 for various stringer core con struction methods Dry fit and
3. If it s necessary for the fasteners to provide clamping pressure on vertical surfaces for exam ple and the existing hole is stripped and has no holding power drill the oversized hole to the full length of the fastener and fill the hole at least 1 4 to 2 3 full with epoxy If the surface is ver tical or overhead first wet out the hole with epoxy then partially fill the hole with an ep oxy 404 or 406 mixture thickened to a non sagging consistency After the epoxy has cured drill a standard sized pilot hole in the epoxy to provide enough holding power for the fastener to clamp the hardware Figure 7 5 right Place the hardware in position temporarily to locate the proper pilot hole locations If the loose hardware was mounted to a non cored single skin panel without blocking see Sec tion 7 1 1 Temporarily place the hardware item in position and trace the outline of the base and the fas tener holes with a pencil Mask off the outside of the marked area and cover the area beyond the tape with plastic sheeting for protection from spills Thoroughly sand the surface within the masked area with coarse sandpaper to provide good mechanical keying for bonding Installing Hardware 52 Epoxy mixture Partially fill with epoxy if core is too damaged to hold Figure 7 5 Drill an oversized hole around each existing fas Figure 7 6 Tighten the fasteners until a small amount of ep tener hole to increase the fastener s bonding
4. This manual begins with techniques for repairing common minor damage to hull and deck sur faces and progresses to more complicated structural repairs Section 2 includes basic surface re pairs and cosmetic finishing Section 3 describes methods for repairing rotted stringers and adding reinforcing to areas of the hull or deck that are too flexible Sections 4 and 5 deal with re pairs of more serious damage to solid and cored hull and deck panels The later sections include specific deck repair and modification hardware attachment and keel and rudder repair After the structural repairs are completed you may be referred back to Section 2 for the surface repair and cosmetic finishing Study and become familiar with all of the steps in a procedure before beginning a repair The procedures described in this manual assume a working knowledge of WEST SYSTEM products and the basic techniques of epoxy use If you are unfamiliar with or have any questions about the application and handling techniques of WEST SYSTEM Brand epoxy products read Section 9 Using WEST SYSTEM Epoxy thoroughly before proceeding with repairs The WEST SYSTEM User Manual c amp Product Guide also provides basic epoxy handling information as well as com plete current product descriptions and selection and coverage information It is a free publica tion available through WEST SYSTEM dealers or by contacting West System Inc Some fiberglass repair procedures can be hazardous Always w
5. Figure 7 7 Hardware casting is a variation of hardware bonding for fittings that must be mounted at specific angles to hull or deck surfaces or mounted to curved or uneven surfaces 2 Position the hardware Mark the outline of the hardware and shim it to its desired angle Mark the shim locations Often one edge of the fitting will rest on the deck and become the zero point for the required angle Wet out the substrate deck surface with resin hardener mixture except for the shim locations 4 Cast epoxy supports under the hardware Figure 7 7a Prepare a mixture of epoxy 404 filler thickened to a peanut butter consistency Use the mixing stick to place three portions of the mixture within the hardware outline evenly spaced around the perimeter Use enough of the mixture and pile the mixture high enough to contact the base of the hardware when it is shimmed in its proper position When cured the epoxy supports will take the place of the tem porary shims Set the fitting in place with the temporary shims holding the hardware at the proper height and angle The bottom of the hardware should contact all three epoxy supports Allow the epoxy supports to cure thoroughly Tap the hardware with a mallet to break it loose and remove the temporary shims Mask off the area around the fitting with duct tape and plastic in case of accidental epoxy spills Prepare the deck and hardware for casting the base Wash and sand the cured epoxy in the de
6. The foam density the depth of the plug the amount of foam expansion in back of the hole and the epoxy content of the foam all affect the holding power of the plug 7 2 Bonding fasteners and hardware Hardware can vary by size type and number of fasteners and the size and direction of the load on the hardware The panel may be cored or a single skin with and often without blocking be hind it The hardware fasteners may be through bolted with washers or a backer plate or screwed to the skin and blocking or simply to a single skin The following procedures describe repairs for through bolted fasteners and for fasteners that do not pass through the panel These repairs combine techniques for advanced fastener bond ing and techniques for bonding the hardware base Through bolted fasteners are used on larger or more heavily loaded hardware Fasteners that are screwed to the skin and core or blocking carry less load and should be used for lighter hardware If the hardware is screwed to a cored or non cored panel follow the procedure in Section 7 2 2 Bonding to metal Bonding the metal hardware base to the substrate provides additional load transfer to the substrate Proper surface preparation beginning with thorough sanding is crucial to getting a good mechanical bond to metal Aluminum requires an additional two step surface preparation The first step involves the use of an acid conditioner that removes corro sion The second step chemic
7. Any adhesive filler is suitable for most bonding situations Your choice of a filler for general use may be based on the handling properties you prefer Fillers may also be blended to provide intermediate properties 9 3 Handling epoxy This section explains the fundamentals of epoxy curing and the steps for proper dispensing mixing and adding fillers to assure that every batch of epoxy cures to a useful high strength solid 9 3 1 Understanding epoxy s cure stages Mixing epoxy resin and hardener begins a chemical reaction that transforms the combined liq uid ingredients to a solid The time it takes for this transformation is the cure time As it cures the epoxy passes from the liquid state through a gel state before it reaches a solid state Figure 9 3 1 Liquid Open time Open time also working time or wet lay up time is the portion of the cure time after mixing that the resin hardener mixture remains a liquid and is workable and suitable for application All assembly and clamping should take place during the open time to assure a dependable bond 2 Gel Initial cure phase The mixture passes into an initial cure phase also called the green stage when it begins to gel or kick off The epoxy is no longer workable and will progress from a tacky gel consistency to the firmness of hard rubber You will be able to dent it with your thumb nail 65 Using WEST SYSTEM Epoxy Figure 9 3 As it cures mixed epoxy
8. Avoid contact with resin hardeners mixed epoxy and sanding dust from epoxy that is not fully cured Wear protective gloves and clothing whenever you handle WEST SYSTEM epoxies Bar rier skin creams provide additional protection If you do get resin hardener or mixed epoxy on your skin remove it as soon as possible Resin is not water soluble use a waterless skin cleanser to remove resin or mixed epoxy from your skin Hardener is water soluble wash with soap and warm water to remove hardener or sanding dust from your skin Always wash thoroughly with soap and warm water after using epoxy Never use solvents to remove epoxy from your skin Stop using the product if you develop a reaction Resume work only after the symptoms disap pear usually after several days When you resume work improve your safety precautions to prevent exposure to epoxy its vapors and sanding dust If problems persist discontinue use and consult a physician Protect your eyes from contact with resin hardeners mixed epoxy and sanding dust by wear ing appropriate eye protection If contact occurs immediately flush the eyes with water under low pressure for 15 minutes If discomfort persists seek medical attention Avoid breathing concentrated vapors and sanding dust WEST SYSTEM epoxies have low VOC content but vapors can build up in unvented spaces Provide ample ventilation when working with epoxy in confined spaces such as boat interiors When adeq
9. Roller covers into segments They are used to tip off coats of epoxy to remove bubbles and roller marks Drag Tools 80 Gelcoat Sprayers For small areas of gelcoat or paint finishing as described in Section 2 2 the Preval Auto Sprayer is a handy self contained reusable sprayer Holds up to 16 oz of custom mixed paints or gel coats It can be purchased at automotive paint supply stores Precision Valve Cor poration Yonkers NY 10703 7 wide brush for large areas two brushes per cover the brush over fresh epoxy in long even overlapping 3 radius strokes after each batch is applied Use enough pressure to smooth the surface without removing epoxy six brushes per cover 3 wide brush for small areas 81 Cold Temperature Bonding and Coating Techniques Appendix C Cold Temperature Bonding and Coating Techniques Epoxy can be used under cold weather conditions but you must use special application tech niques These precautions are not elaborate or difficult but they are necessary to achieve ac ceptable long term epoxy performance These precautions do not apply to WEST SYSTEM epoxy alone any epoxy used in critical marine structural situations may have its capabilities and performance affected by cold weather In fact due to differences in formulation not all epoxies possess the necessary characteristics to ever cure well under cold weather conditions Chemical characteristics
10. There is also a strong possibility the impact that damaged the panel may have caused internal structural damage to bulkheads frames etc Any such damage should be re paired prior to undertaking the repair of the cored panel The objective in repairing holes through cored panels is to replace damaged core material and restore skin continuity to both skins The sequence of skin and core replacement will vary de pending on access to the back of the panel 5 4 1 Repairing holes through cored panels with back access Figure 5 13 Grind a 12 to 1 bevel on the edges of the inner Figure 5 14 Brace a temporary backing against the back of and outer skins 2 i i F l i Fj a ON a Ps Plastic ct te i N 12 D 1 bevel se sce ad N After preparing the hole replace the core material and laminate the inner and outer skin to the core as follows Prepare the hole by cutting away ragged or damaged skin Cut back to undamaged core and skin while maintaining a circular or oval hole shape Grind a minimum 12 to 1 bevel on the edges of the inner and outer skins at the hole to provide adequate bonding surface when re laminating the skin repair patches For example if the skin is 1 4 6mm thick the bevel will extend 3 7 5cm from the edge of the hole Figure 5 13 New core 4 a ae i j i ea as pt 3 j i I 4 i J ra a a fm Temporary P34 aed ie d d j iy d a F Pi T i i r Sa FOL Pm foam backer
11. Unless the damage is directly attributable to an undersized stringer assume that the stringers were structurally adequate and properly located when the boat was originally built Making a repair that is significantly stronger than the original design can cause hard spots that may distort or crack the hull shell A repair that is lighter than the original may fail prematurely When removing and replacing stringer material observe the following guidelines Duplicate the shape and dimensions of the original stringer Where the stringer is supporting a cockpit sole cabin sole or engine the height of the repaired or replaced stringer must be the same as the original If not you will have a great deal of difficulty reinstalling the equipment Duplicate the original core material or find an equivalent material Use wood where wood was used ply wood for plywood foam for foam etc Attempt to duplicate the species of wood used in the stringer as well as the dimensions of the wood You can use a more cavalier approach to replac ing low density core materials than you can for active cores Measure the thickness of the fiberglass skin and duplicate it On stringers with an inactive core or molded stringers with no core watch for variations in the skin thickness Occasionally the top skin of the stringer is thicker than the side skins This cap can significantly increase the strength and stiffness of the stringer If the extra thickness is pre
12. When you mix an epoxy resin and hardener together you start a chemical reaction which as a byproduct produces heat This is called an exothermic reaction The ambient temperature in which an epoxy chemical reaction takes place affects the rate of reaction Warmer temperatures accelerate the reaction time while cooler temperatures retard it Duration of reaction among other variables influences inter bonding of the epoxy molecules If the reaction is too slow even though the epoxy may harden it may not cure completely and possibly never achieve its designed physical properties This is where danger lies for improp erly cured epoxy may possess enough strength to hold a structure together yet it may fail after repeated loadings during normal operation Working properties Temperature has a profound effect on the working properties of uncured epoxy Ambient tem perature changes will drastically change the epoxy s viscosity thickness Viscosity of water varies little with temperature changes until it either boils or freezes Epoxy however is made of heavier molecules and temperature can have an effect that is 10 times greater on epoxy mole cules than on water molecules over a temperature change of 30 F 16 C The colder it gets the thicker the epoxy becomes reducing its ability to flow out This kind of change has three important consequences for working with epoxy under cold conditions First it is more difficult to mix the res
13. staples or 5 small nails to apply enough pressure to squeeze a small amount of epoxy from each joint Remove the stringer from the jig after the epoxy has thoroughly cured Be sure to allow extra cure time if the temperature is cool especially if you expect a lot of springback Trim laminated stringers to final shape Install new stringers as described in section 3 4 Apply fiberglass fabric over the stringers as de scribed in section 3 5 If you have added stringers to an exposed interior area you may not want to or need to apply fiberglass over them Wood stringers especially the laminated type can en hance the appearance of your boat s interior They provide a nice touch when varnished while they serve their primary function of reinforcement If you choose to coat the stringers sand the stringers and fillets to prepare for bonding Apply two or three coats of epoxy to seal the stringer Allow the final coat to cure thoroughly Half round and foam cores Half round or foam reinforcements with a fiberglass skin are a simple way of strengthening panels With this method the core material primarily serves as a form and the laminated fiber glass fabric provides the stiffening strength For light duty applications an economical core material for this method of reinforcement is a cardboard or paper tube cut in half lengthwise Pieces can be placed end to end to reinforce larger areas The tube should be heavy enough to hold its shape
14. absorb some of the energy incurred upon impact or grounding Its ability to deform reduces the intensity of shock loads to the hull and can prevent serious structural damage to a hull However the deformation of the lead keel can measurably affect overall sailing performance Fortunately repairing this type of damage is a relatively modest project To repair an externally ballasted lead keel deformed from impact or grounding proceed as follows 1 Be certain damaged area of the keel is accessible when the boat is hauled from the water Dry the keel thoroughly A heat gun or heat lamp will speed drying 2 Remove any loose chips of lead or filling materials Scrub the repair area with a wire brush to re move any remaining surface contamination and to expose fresh lead Wear a dust mask Figure 8 2 Use a ball peen hammer with repeated light taps Figure 8 3 Plane or file the remainder of the bulge flush after to work the lead bulge back to its original shape you have forged as much as is practical 57 Repairing Keels and Rudders Forge displaced lead toward voids with a ball peen hammer As the lead is deformed from an impact it s common to find a bulge to one or both sides of a dent or gouge Use repeated light taps to work the lead back to its original shape Figure 8 2 Too heavy a blow will shear sections of lead With experience you will soon be able to gauge how much force you can use and how much lead can be moved before sh
15. adhesive fillers can be used And for most surface filling either of the fairing fillers can be used Fillers may also be blended for intermediate characteristics Adhesive fillers 403 Microfibers For general bonding and gap filling Epoxy 403 mixtures have superior gap filling qualities and good strength for most bonding applications while retaining wet ting penetrating capabilities Works especially well with porous woods Cures to an off white color 404 High Density Filler For hardware fastener bonding and applications that require maxi mum physical properties and where high cyclic loads are anticipated Also used for gap filling where maximum strength is necessary Cures to an off white color 405 Filleting Blend For use in bonding and filleting on naturally finished wood projects A strong wood toned filler that mixes easily and spreads smoothly Cures to a brown color and can be used to tint other fillers Using WEST SYSTEM Epoxy 64 406 Colloidal Silica For general bonding gap filling high strength bonds and fillets A prac tical and versatile smooth textured filler Can be used alone or mixed with other fillers to im prove workability and smoothness Cures to an off white color Fairing fillers 407 Low Density Filler A blended microballoon based filler used to make a fairing com pound that is easy to sand or carve while still being reasonably strong on a strength to weight basis Cures to a reddish brown color
16. and sand it to prepare for the final finish 9 4 7 Final surface preparation 1 Proper finishing techniques will not only add beauty to your efforts but will also protect your work from ultraviolet light which will break down the epoxy over time The most common methods of finishing are painting or varnishing These coating systems protect the epoxy from ultraviolet light and require proper preparation of the surface before application Preparation for the final finish is just as important as it is for recoating with epoxy The surface must first be clean dry and sanded Section 9 4 1 Allow the final epoxy coat to cure thoroughly 2 Wash the surface with a Scotch brite pad and water Dry with paper towels 3 Sand toasmooth finish If there are runs or sags begin sanding with 80 grit paper to remove the highest areas Sand until the surface feels and looks fair Complete sanding with the appropriate grit for the type of coating to be applied Generally the thinner the coating the finer the grit Paint adhesion relies on the mechanical grip of the paint keying into the sanding scratches in the epoxy s surface If a high build or filling primer is to be applied 80 100 grit is usually suffi Using WEST SYSTEM Epoxy 78 cient For primers and high solids coatings 120 180 grit may be adequate Finishing with 220 400 grit paper is often recommended for coatings with high gloss finishes Grits finer than this may not provide en
17. apply additional material over non curing epoxy See 9 3 5 Removing epoxy 2 Mix resin and hardener together thoroughly to avoid resin rich and hardener rich areas 3 Add fillers or additives after resin and hardener have been thoroughly mixed See 9 3 3 Dispensing and mixing 1 Remove epoxy Do not apply additional material over non curing epoxy See 9 3 5 Removing epoxy 2 Check for proper resin and hardener Resin will not cure properly with other brands of hardener or with polyester catalysts See above Wet out bonding surfaces before applying thickened ep oxy Re wet very porous surfaces and end grain See 9 4 2 Bonding TIwo step bonding Clean and sand the surface following the procedure in 9 4 1 Surface preparation Sand wood surfaces after planing or joining Increase bonding area by adding fillets bonded fasteners or scarf joints Use just enough clamping pressure to squeeze a small amount of epoxy from the joint 1 Apply moderate heat to partially cured coating to re move moisture and complete the cure Avoid overheating 2 Use 207 Hardener for clear coating applications and for bonding thin veneers that may bleed through to the sur face 1 Apply moderate heat to partially cured coating to re lease trapped air and complete the cure Avoid overheat ing 1 Apply coating at warmer temperature epoxy is thinner at warmer temperatures 2 Apply epoxy in thin coats Blush formation is typica
18. areas it lends it self better to small areas where it s necessary to color match existing gelcoat and its handling characteristics are more manageable Linear polyurethane paints give extremely durable fin ishes and are appropriate for large complete sections like a hull or deck where color matching is not critical Paint application over a large area is more practical than gelcoat These finishes are recommended for above the waterline only Use WEST SYSTEM for all repairs and coating below the waterline prior to applying bottom paint 2 2 1 Gelcoat finishes In answer to questions concerning compatibility and techniques for applying polyester gelcoats over repairs made with WEST SYSTEM epoxy we can say epoxy provides an excellent base for polyester gelcoats The following procedure will assure good adhesion and a well matched re pair color If you have only a shallow crack or scrape that does not extend into the laminate be gin with Step 1 If you have repaired minor cracks or scrapes with epoxy and are ready to proceed with the final gelcoat finish begin with Step 4 Be sure the epoxy has cured thoroughly Wash the surface thoroughly to remove all traces of amine blush Remove any surface contaminants such as wax oil or mold release Wipe an area at least twice as large as the damaged area with a wax and silicone remover Dupont Prep Sol 3919S ac etone or appropriate solvent Dry the area with clean paper towels before the solv
19. during the lay up and cure of the fabric laminate Low density foam also makes an economical core material Cut the foam on a table or band saw to a trapezoid shaped cross section The trapezoidal cross section is more ef fective than the half round cross section because it places more reinforcing fibers on the top of the stringer away from the stringer s neutral axis Cut a4 to 1 bevel on ends that fall in the mid dle of a panel Sand a radius on the top edges Repairing Stringers and Floor 20 Figure 3 10 The half round material serves as a form for the laminated fiberglass fab ric that provides the stiff ness To bond half round tubes Apply a 1 4 6mm bead of thickened epoxy mixture to the out lined edge of the bonding surface Mix epoxy 404 or 406 filler to the consistency of peanut but ter Place the tube stringer in position in the thickened epoxy beads The epoxy mixture should hold it in place Shape the epoxy bead on the outside of the stringer panel joint into a fillet Ap ply additional thickened epoxy to the joint if necessary for a smooth 4 radius fillet If neces sary brace or tape the stringer in position until the epoxy reaches an initial cure Apply fiberglass fabric as described in Section 3 5 Remember more layers of fiberglass reinforcing are required over inactive cores 3 5 4 Reinforcing with unidirectional fibers The stiffness of reinforcement stringers can be significantly improved with little w
20. guide Sand the ridges on either side of the template impres sion flush with the profile Avoid sanding into the profile You should be left with smooth bands of fairing compound at the root midpoint and tip of the keel that will be used as profile guides to accurately apply the remaining fairing material Use the templates to check the profiles and sand or add filler to the profile as necessary to match the template 8 Wet out the surface between the guides with epoxy Allow the coating to gel Mix enough epoxy 407 or 410 fairing compound to fill the area between two of the profile guides Use the same filler and filler consistency used to make the guides With a plastic squee gee or custom spreader apply the mixture to the middle area of the foil Leave the mixture higher than the guides 59 Repairing Keels and Rudders Match keel center line Release fabric Template ya Guides Release fabric Cm Figure 8 6 Make an impression of each template profile in Figure 8 7 Using the cast template profiles as guides drag a the epoxy mixture Sand the excess mixture flush with the pro batten across the profiles to level the fresh epoxy mixture flush file after the mixture has cured with the three profiles 10 11 12 Lay a precut piece of release fabric over the fairing compound The fabric should be large enough to cover the entire area from guide to guide Using a length of 11 2 diameter PVC
21. hardware loads We recommend adhesive bonding to all hardware and fasteners rather than the use of mold release whenever possible 7 5 Removing bonded hardware Occasionally it is necessary to remove bonded hardware items At temperatures above 150 F 66 C cured epoxy begins to lose its physical properties the resin softens and its bonding ca pacity is reduced considerably You can use this characteristic to your advantage when you would like to remove a piece of bonded hardware 1 Remove all fasteners If you used a release agent on them when you bonded the piece in place they should come loose without too much difficulty If the fasteners were bonded in it will be necessary to apply heat to them using a soldering iron The epoxy around the fastener will soften enough to loosen the fastener when enough heat is conducted down the fastener 2 Heat the fitting briefly with a propane torch Protect the area around the fitting from heat dam age by covering with water soaked plywood Allow the heat to conduct through the base of the hardware A sharp rap with a mallet should be enough to dislodge the hardware If the fitting doesn t break loose easily the first time don t force it Heat it a second time with the torch and try again 3 Replace the hardware by following the procedures in Section 7 1 1 Re drill the fastener holes in the existing epoxy as you would for a new installation E 55 Repairing Keels and Rudders 8 Repa
22. is a practical and beautiful option for finishing a deck or sole repair or for em Thinner teak veneers 4 3mm 6mm can be applied to decks seats cabin tops or hatches without adding excessive weight When installing veneers the gap between the strips is filled with an epoxy 404 graphite mixture to give you an authentic teak deck that is both durable and low in maintenance Thicker teak planks 14 34 6mm 19mm are also bonded to the substrate but the gap be tween planks is filled with a flexible caulk more suited to the greater expansion and contraction of thicker material This is similar to traditional methods but with the advantage of a reliable moisture barrier under the teak and no fasteners penetrating the substrate 6 2 1 Installing teak veneers Although strips of up to 4 6mm thickness may be used the effects of dimensional change can be limited by using thinner 3mm thick strips A thick deck will provide you with years of service in high traffic areas and it will keep the additional weight of anew teak deck to a min imum Strips should be 14 2 2 38mm 50mm wide with edges planed smooth and straight Leave the flat surfaces top and bottom rough sawn The rough texture left by the saw im 45 Repairing and Upgrading Soles and Decks A Edge grained strips 7 777 a o i j j p yp Figure 6 3 Alternate methods for cutting edge grained deck Figure 6 4 Cut and fit the teak strips Mask of
23. or 406 filler to the consistency of catsup and apply it with a dis posable brush Lay the fabric in position on the repair area Use a plastic spreader to smooth the cloth and re move trapped air 12 to 1 minimum bevel Release Glass fabric fabric Release fabric Figure 4 5 Cut an appropriate number of pieces of fi Figure 4 6 Squeegee over the release fabric with berglass fabric The first piece should match the out firm pressure to remove excess epoxy and smooth side edge of the bevel the patch Wet out the fabric Use a plastic spreader or roller to spread the epoxy and saturate all areas of the fabric Repeat the process for each layer of fabric until you have bonded the smallest piece in place last centered over the hole By bonding the patch into place in a large to small piece sequence you will eliminate the possibility of sanding through any of the cloth layers when fairing the surface Apply epoxy fairing compound epoxy thickened with 407 or 410 filler over the repair when epoxy fiberglass patch begins to gel Apply the fairing compound when the epoxy is still tacky Refer to Section 9 4 4 for fairing details Repairing Damaged Skins 26 An optional method is to finish the repair in two stages Cut a piece of release fabric several inches larger than the patch and smooth it in place over the patch Squeegee over the release fab ric with firm pressure to remove excess epoxy and smooth the patch Figur
24. pipe cut to span two of the guides shape the fairing mixture flush with the guides Beginning in the middle of the foil roll the pipe back and forth as you would a rolling pin forcing fairing com pound under the release fabric toward the leading and trailing edges of the foil Figure 8 7 Ad just the angle of the pipe as you approach the edges of the foil to finish with the pipe parallel to the leading and trailing edges With the proper amount of fairing compound a small amount of excess will squeeze from the leading and trailing edge To give yourself adequate working time in warmer temperatures use 206 or 209 Hardener Allow the fairing mixture to cure thoroughly Remove the release fabric Repeat the process on the remaining areas Fill any large remaining low areas using the same procedure after the fairing compound has cured Repeat as necessary until you are satisfied with the shape and fairness of the surface Sand the cured surface as necessary It should require only minor local fairing When you are satisfied with the fairness and smoothness apply an epoxy barrier coat and finish as described in Section 2 8 4 Repairing worn rudder bearings Common wear points on sailboats with spade type rudders are the bearings that support the rudder shaft Worn bearings can result in sloppy steering and an irritating thump as the rudder shaft flops from side to side in the enlarged bearing Worn bearings can also detract from the precise sen
25. remaining voids with the epoxy 407 filler mixture thickened to a peanut butter consistency Sand again when cured and coat the entire repair area with three coats of epoxy Complete the final sand ing and application of bottom paint after the final coat has cured thoroughly 8 3 Templating keels and rudders Few production boats achieve the designer s intended underwater shape and for most boats the difference is close enough For those interested in getting a little more performance from their boat most racing classes will allow the skipper to attempt to fair the hull closer to the designer s original specifications without having these changes considered modifications Profile shape and section offsets are usually available from either the class association or the boat s designer If foil profiles are not available you may design your own foil shape Informa tion on lofting foil shapes for keels and rudders is available by calling or writing the West System technical staff The object of this procedure is to reshape the keel or rudder to more closely match the designed foil shape Although the procedure describes keel templating the same procedure applies to rudders Obtain the profiles for three locations on the keel the root top of the keel near the hull attach ment point the midpoint and the tip of the keel Enlarge the profiles as necessary to full size Repairing Keels and Rudders 58 Figure 8 5 Transfer th
26. remaining plywood one layer at a time 37 Repairing Core Related Damage Figure 5 11 Bond a new plywood core in place Laminate sheets of thinner plywood to equal the thick ness of the old core Trim the pieces to fit the void left by the old core use a card board template to layout pieces Cut the pieces as necessary to fit opening 6 Recheck the fit of the final pieces and be sure to sand cured epoxy coated surfaces prior to lami 7 nating additional plywood layers Repeat the process for each layer Use drywall screws to draw the new layer down to the first layer Remove the screws and fill the holes with epoxy after the epoxy cures or if you plan to leave the fasteners in place be sure they are stainless galvanized or bronze An alternative method is to install and clamp all the layers in place at the same time if a very slow curing hardener 209 Extra Slow is used Dry fit and label all of the parts Apply unthickened epoxy to all of the plywood segments especially the end grain around the perimeter of each piece before applying thickened epoxy Pieces can be temporarily clamped with drywall screws Remove and replace the screws as each layer is installed 5 3 5 Replace the fiberglass skin 2 3 After the core replacement is complete the original fiberglass skin can be laminated over the new core or if necessary a new skin can be laminated over the core A transom skin is often reusable except for a relat
27. skin continuity and structural properties of the core to equal or greater strength than the original E Repairing and Upgrading Soles and Decks 42 6 Repairing and Upgrading Soles and Decks A common source of problems on open runabouts and pontoon boats is the cockpit sole or deck Poorly installed soles and decks are prone to delamination and rot The first part of this section describes how to remove and replace damaged plywood decks The second part de scribes how to install a teak veneer deck that is a practical and beautiful option for finishing a deck repair 6 1 Repairing delaminated soles and decks On runabouts the plywood cockpit sole is usually just a layer of plywood screwed down to the top of stringers and frames and tabbed or joined to the hull sides with fiberglass tape at the edges of the plywood and up the side of the hull a few inches Some runabouts will also have a layer or two of fiberglass fabric over the top of the plywood with a non skid pattern molded in Many have a layer of carpet or vinyl flooring material glued onto the plywood that can trap moisture and contribute to delamination and rot Moisture enters the plywood end grain alongside of the screws holding the sole down to the framing as well as the fasteners holding the seats coolers and other items to the sole Moisture also penetrates and damages the stringers supporting the sole See Section 3 Repairing String ers and Floors In addition there i
28. that is most appropriate to your situation and keep in mind that the objective is to restore the structural properties of the panel by rebuilding the load carrying ability of the core and the skins to the original or greater strength 5 1 Repairing skin delamination Skin delamination is often first noticed when you step on a flexible or spongy area on an other wise firm deck Most delamination is a result of moisture damage to the skin core bond and usu ally involves balsa core or plywood cored panels Moisture entering cracks or nearby loose hardware can migrate much more easily through these cores than a foam core Also balsa and 29 Repairing Core Related Damage plywood cores are much less expensive and more widely used than foam cores in production boats Often the core material will be wet or even saturated but it may still be serviceable if dried thoroughly However if a wooden core remains wet long enough it will begin to deterio rate and will need replacement Delamination can also occur in isolated pockets as a result of inadequate core bonding during man ufacture In some cases the core may remain dry and undamaged and simply need re bonding 5 1 1 Assessing delamination damage The first step in the repair is to determine the extent of delamination and the condition of the core Then follow the repair procedure most appropriate to your situation Locate and mark the extent of the damage by exerting pressure on the pane
29. the epoxy is applied to a surface with a different temperature Generally epoxy cures faster when the air temperature is warmer Exothermic heat is produced by the chemical reaction that cures epoxy The amount of heat produced depends on the thickness or exposed surface area of mixed epoxy In a thicker mass Using WEST SYSTEM Epoxy 66 more heat is retained causing a faster reaction and more heat The mixing container shape and mixed quantity have a great affect on this exothermic reaction A contained mass of curing ep oxy 8 fl oz or more in a plastic mixing cup can quickly generate enough heat to melt the cup and burn your skin However if the same quantity is spread into a thin layer exothermic heat is dissipated and the epoxy s cure time is determined by the ambient temperature The thinner the layer of curing epoxy the less it is affected by exothermic heat and the slower it cures Controlling cure time In warm conditions use a slower hardener if possible Mix smaller batches that can be used up quickly or quickly pour the epoxy mixture into a container with greater surface area a roller pan for example thereby allowing exothermic heat to dissipate and extending open time The sooner the mixture is transferred or applied after thorough mixing the more of the mixture s useful open time will be available for coating lay up or assembly In cool conditions use a faster hardener or use supplemental heat to raise the epo
30. the matching bevel on the wood that remains in the stringer is not as easy Use chisels disc grinders hand planes hand saws and any other useful tool available to you to cut wood and fiberglass The surface of the bevel does not have to be perfect Cut out the damaged section of the existing stringer Remove as much skin as necessary to re move all of the damaged core Trim the exposed core ends to a minimum 8 to 1 scarf angle Fig ure 3 3 The scarf may run vertically or horizontally Figure 3 3 Trim a new piece of core material to fit the size and shape of the void in the existing core The scarf may Trim exposed run vertically or hori coreendsto zontally an 8 to 1 scarf angle 2 Prepare for the skin replacement Prepare both sides of the joint to achieve a good bond 3 Trim anew piece of core material to fit the size and shape of the void in the existing core Use the same species of wood as the existing core Cut a matching scarf angle on each end of the new core section Dry fit and trim the new piece and existing core ends as necessary for a good fit Prepare the surfaces for bonding All surfaces should be clean dry and sanded Install the new core section Wet out all contact surfaces of the new and existing core Apply a liberal amount of thickened epoxy 406 mixture to one side of each contact area Depending on the fit of the new core use enough thickened epoxy to bridge all gaps between the two surfaces
31. the repair patch For most repair situations vacuum bag ging is not necessary for a sound repair Vacuum bagging is useful in situations where compac tion of the laminate is required as in lightweight or high performance structures It is also useful is situations where conventional clamping is not practical when bonding large areas of core material for example 12 to 1 bevel around Figure 4 9 Smooth damagedarea vacuum bag deer the patch and the re Mastic lease fabric in place Breather fabric Lay the vacuum bag Release me material over the iy 77 Vacuum atch seal the ba gauge amp dy j if and attach vacuum uy W i Fiberglass cloth F4 y Re Mastic or adhesive y Plastic laminate lines The lay up procedure for vacuum bagging a small repair is the same as for the repair described above except for the following steps 1 Prepare all vacuum bagging materials before mixing epoxy Apply a continuous strip of vacuum bag sealant around the perimeter of the repair area before mixing epoxy Laminate the repair patch following either of the above procedures 4 After smoothing the patch and release fabric in place lay the vacuum bag material over the patch Figure 4 9 Remove the protective paper from the vacuum bag sealant and press the bag into the sealant around the perimeter The lay up must be airtight Seal off scored or porous core material or delaminated skin and core
32. the tip at an angle Fill the sy ringe with an epoxy 406 filler mixture thickened to the consistency of catsup Inject the epoxy mixture under the skin through each of the inspection holes The shortened ta 7 pered syringe tip will fit tightly in the 6 2 inspection holes Figure 5 1 You should be able to develop enough pressure to force the epoxy several inches from the hole Clamp the skin to the core when you are sure you have injected enough epoxy to bridge any gaps between the skin and core Use weights braces or sheet metal screws through the inspec tion holes to hold the skin tight and fair against the core until the epoxy cures Clean up excess epoxy before it begins to gel Allow the epoxy to cure thoroughly before removing clamps Figure 5 1 Inject epoxy under the skin using an 807 syringe with the tip cut off to match the hole diameter Repairing Core Related Damage 30 4 Fill any voids in the inspection holes with a thick epoxy 406 filler mixture after removing clamps When the epoxy has cured thoroughly fair and finish the surface as described in Section 2 5 1 3 Re bonding delaminated skin to a wet core If the core material is wet but still solid re bond the skin after the core has been thoroughly dried One of two methods may be used to expose the core for drying Pattern hole drying method This method involves drilling a pattern of holes through the skin to expose the core to air and he
33. to provide the structural framework for wooden boats They support cockpit and cabin soles and they distribute high load concentrations from engines and other mechanical systems Often they perform several of these functions simultaneously In fiberglass boats you will find that most often stringers and floors are composed of a core material overlaid with a fiberglass skin The skin usually extends a few inches on either side of the stringer This skin extension or tabbing ties the stringer to the hull or bulkheads and spreads the load of the stringer over a larger area Tabbing may be a simple piece of glass tape across the stringer hull joint or an integral structural part of the stringer Some cores are struc tural or active and some are inactive used primarily to provide a form for a structural fiberglass skin Active core stringers with cores of solid wood or plywood rely on the structural properties of the wood core itself to provide stiffness Generally the more dense the core material like wood or plywood the more of the load it is expected to carry The fiberglass skin covering an active core is primarily used to protect the wood and to attach it to the hull It is generally thinner than the skin on inactive core When you replace structural cores you have to use proper scarf bevels or other proper means of piecing the new core into the old Figure 3 1 Some cores are structural or active and some are inactive us
34. to set the new plywood on The sole may be bonded to the stringers and cleats supporting it If necessary cut the sole out in sections then chisel and grind away any material bonded to the tops of the stringers 6 1 2 Installing the new sole The moisture that damaged the plywood sole could have also damaged the stringers and floors supporting it It s a good idea to inspect and repair all damage to the structure below the sole be fore reinstalling the sole If the structure is in good shape reinstall the sole as follows Cut out new pieces of plywood using careful measurements or the patterns from the old sole Make sure the new plywood is at least the same thickness as the original material 2 Dry fit the sections and drill any fastener holes and then remove the section Coat the back side with two or three coats of epoxy before reinstalling to prevent moisture from penetrating the bottom of the new sole It is also very important to completely seal the edges of the plywood and the fastener holes Sealing the edges of the plywood is especially important at the edges of a deck ona pontoon boat If using Douglas fir plywood you should use a light layer of woven fiberglass fabric on both sides to prevent checking 6 oz glass is usually sufficient Bond the new plywood sole to the hull to the stringers and floors and to any cleats installed to support the edges of the plywood between stringers Use a thick epoxy adhesive filler
35. trim the new piece for a good fit 4 Prepare the surfaces for bonding All surfaces should be clean dry and sanded Remove any traces of contamination by wiping the surface with solvent and drying with paper towels before the solvent evaporates Use a degreaser or detergent in areas that may be contaminated with gas oline or oil residue before wiping with solvent Use a stiff nylon bristle brush on heavily tex tured surfaces like roving Abrade the bonding surfaces by sanding with 50 grit sandpaper and brush the area free of dust or loose material Use a wire brush to abrade heavily textured sur faces The bonding surface should appear dull Sand the bonding surfaces of hardwood or epoxy coated stringers with 50 grit sandpaper 5 Wet out all contact surfaces of the hull and core with epoxy Apply a liberal amount of thick ened epoxy 404 High Density or 406 Colloidal Silica mixture to one side of the contact area Figure 3 4 Epoxy mixture should squeeze out of the joint Shape the squeezed out epoxy into a fillet Round over edges Fillet 6 Push the stringer in position with firm hand pressure Thickened epoxy should squeeze out of the joint Brace or tape the stringer in position as necessary 7 Shape the squeezed out epoxy into a fillet Apply additional thickened epoxy to the joint if nec essary for a smooth 1 2 radius fillet Clean up excess epoxy before it cures Remove clamps after epoxy cures thoroughly 8 Rep
36. wire brush to abrade heavily textured surfaces The bonding surface should appear dull A 12 to 1 bevel must be ground into any existing fiberglass left on a stringer The new fiberglass will run onto this bevel attaching the new material to the original material A 12 to 1 bevel pro vides adequate surface area for the transfer of loads across the repair area For example if the skin on the original portion of the stringer is 4 thick the bevel needs to be 12 x 4 or 3 wide It is difficult to lay fiberglass cloth around a sharp 90 corner You have to round over the top edges of the cores and fillet the core hull and core bulkhead inside corners a 34 radius for thinner fabric 1 2 radius for thicker fabric Applying the fiberglass skin 1 Prepare fiberglass fabric and bonding surfaces as described above 2 Wet out the entire bonding surface including the stringer with a mixture of resin hardener Squeegee a thin layer of thickened epoxy over the exposed panel bonding area if the surface is heavily textured Mix epoxy 404 High Density or 406 Colloidal Silica filler to the consistency of mayonnaise The thickened epoxy will fill voids on the surface and provide better contact with the first layer of fabric Center the largest piece of fabric over the stringer and reinforcement area and wet it out with the resin hardener mixture Squeegee any excess epoxy from the surface making sure the entire piece of fabric has been satura
37. with a plastic spreader working it into all voids and de pressions Smooth the mixture to the desired shape leaving the mixture slightly higher than the surrounding area Figure 9 15 Remove any excess thickened epoxy before it cures If the voids you are filling are over 1 2 deep apply the mixture in several applications or use 206 Slow Hard ener or 209 Tropical Hardener depending on ambient temperature Allow the final thickened epoxy application to cure thoroughly Sand the fairing material to blend with the surrounding contour Figure 9 16 Begin with 50 grit sandpaper if you have a lot of fairing material to remove Use 80 grit paper on the ap propriate sanding block when you are close to the final contour CAUTION Don t forget your dust mask Remove the sanding dust and fill any remaining voids following the same procedure Figure 9 16 Sand the fairing material to blend with the sur rounding contour Using WEST SYSTEM Epoxy 74 7 Apply several coats of resin hardener to the area with a disposable brush or roller after you are satisfied with the fairness Allow the final coat to cure thoroughly before final sanding and finishing 9 4 5 Applying woven cloth and tape Fiberglass cloth is applied to surfaces to provide reinforcement and or abrasion resistance or in the case of Douglas Fir plywood to prevent grain checking It is usually applied after fairing and shaping are completed and before the final coati
38. with epoxy Attach the vacuum lines and pump Begin applying vacuum pressure before the epoxy begins to cure Check for air leaks through the back patch and around the mastic sealant Maintain vac uum pressure until the epoxy is cured Remove the vacuum bag and release fabric Sand to re move any high spots Fair the repair as described in Section 9 4 4 Finish the repair as described in Section 2 2 E Repairing Core Related Damage 28 5 Repairing Core Related Damage As mentioned in Section 1 the core material separating the two skins of a cored panel reduces the tensile and compressive loads on the skins and allows a structural panel to withstand greater bending loads without a proportional increase in weight To do this the core material must re main bonded to both skins and be able to resist compression loads applied by the skins when the panel bends The previous section provided procedures for the repair of damaged skins This section de scribes how to restore the core to skin bond and or the structural properties of the core Al though the skin itself may not be damaged it may be necessary to cut or remove a portion of the skin for access to the core Repair or replacement of core material nearly always involves some degree of skin repair requiring you to refer back to the procedures in the previous section 5 0 1 Types of core related damage Core related damage can vary from a small skin delamination with little or no actua
39. 0 0 Ib 15 2 oz 45 6 oz 30 0 Ib 8 0 oz 1 9 oz 6 0 oz 10 0 Ib 4 0 oz 12 0 oz 14 0 Ib 2 0 oz 5 0 oz 4 0 Ib Product number 740 Fabric weight 4 oz Single layer n thickness 008 Quantity of mixed epoxy required for Catsup consistency 3 8 qt 3 2 gal 48 0 gal 1 2 qt 3 6 qt 9 4 gal 9 at 1 3 qt 1 1 gal 27 0 gal 5 qt 1 7 qt 6 0 gal 1 2 qt 3 0 qt 8 9 gal Mayonnaise consistency Peanut butter consistency 2 5 qt 1 0 qt 2 0 gal 9 gal 32 0 gal 15 3 gal 9 qt 7 qt 2 8 qt 2 0 qt 7 4 gal 5 3 gal qt 6 qt 9 qt 5 qt 3 0 qt 1 7 qt 16 0 gal 6 0 gal 4 qt 3 qt 1 3 qt 1 0 qt 4 8 gal 3 7 gal 9 qt qt 2 4 qt 1 8 qt 7 2 gal 5 6 gal 742 729 745 737 738 60z 9oz 12 oz 15 oz 22 oz 010 017 020 033 040 Average of multiple layers applied by hand lay up Shelf life If the containers are kept sealed when not in use WEST SYSTEM resin and hardeners should remain usable for many years Over time 105 Resin will thicken slightly and will therefore require extra care when mixing Hard eners may darken with age but physical proper ties are not affected by color Mini Pumps may be left in containers during storage It is a good idea after a long storage to ver ify the metering accuracy of the pumps and mix a test batch to assure proper curing before applying epoxy to your project Appendix B Tools Most fiberglass re
40. 002 550 Fiberglass Boat Repair amp Maintenance Repairing restoring and prolonging the life of fiberglass boats with WEST SYSTEM Brand Epoxy Contents 1 Introduction Understanding fiberglass boat construction and using WEST SYSTEM Epoxy for repair 2 Repairing Minor Cracks and Holes Repairing and finishing surface and gelcoat damage 3 Repairing Stringers and Floors Repairing rotted stringers and floors and adding reinforcing to increase panel stiffness 4 Repairing Solid Fiberglass Laminate Assessing and repairing structural damage to solid fiberglass laminate 5 Repairing Cored Fiberglass Laminate Repairing delaminated cores and replacing damaged core material 6 Repairing and Upgrading Soles and Decks Repairing delaminated plywood soles and decks and installing a teak veneer deck 7 Installing Hardware Installing new hardware and repairing loose hardware with improved load carrying ability 8 Repairing Keels and Rudders Repairing impact damage and worn rudder bearings templating keels and rudders 9 Using WEST SYSTEM Epoxy Using WEST SYSTEM products safely and effectively Appendix Estimating guide for WEST SYSTEM products Tools Cold temperature bonding and coating techniques Problem solving guide Index BRAND Catalog Number 002 550 Fiberglass Boat Repair amp Maintenance Repairing restoring and prolonging the life of fiberglass boats with WEST SYSTEM Brand epoxy 14th Edition December 2006 T
41. Soles and Decks 46 10 sheet metal screw Fill holes with epoxy _ Fill holes and gap with epoxy 404 423 Flexible caulk J Sand flush h THICK STRIPS veneers 4 THICK STRIPS planks Figure 6 5 Teak veneer and teak plank installations cross section Clamp strips in position with 10 sheet metal screws and washers Sand the surface of veneers and planks after the epoxy cures thoroughly Caulk the gap between planks after sanding 6 Clamp the strips in place with 10 sheet metal screws and large washers Place the screws and washers between the strips 8 20cm apart Each row of screws will clamp the edges of two ad joining planks and act as spacers Figure 6 5 left Coat the screws and washers with a mold re lease cooking nonstick spray or place a small sheet of plastic under the washers to prevent bonding Washers may also be cut from stiff plastic thin wood lath covered with plastic or sim ilar stock with holes drilled for the screws Push adjoining strips tight against the screws before tightening the screws completely Tighten the screws enough to hold the strips firmly and force some of the epoxy mixture to squeeze up between the strips Fill any voids between the planks with the epoxy 404 423 Graphite mixture and smooth the ex cess epoxy flush with the surface of the teak strips Scrape up excess epoxy around the outside edges of the set of strips before the epoxy begins to gel 7 Bond the rema
42. a spreader 5 Apply asecond coat of epoxy with a foam roller Apply enough epoxy to thoroughly wet out the cloth 6 Remove the excess epoxy with a spreader using long overlapping strokes The cloth should ap pear consistently transparent with a smooth cloth texture 7 Follow steps 7 8 and 9 under the dry method to finish the procedure Any remaining irregularities or transitions between cloth and substrate can be faired by using an epoxy filler fairing compound if the surface is to be painted Any additional fairing done after the final coating should receive several additional coats over the faired area Note A third alternative a variation of both methods is to apply the fabric after a wet out coat has reached an initial cure Follow the first three steps of the Wet Method but wait until the ep oxy cures dry to the touch before positioning the fabric and continuing with Step 3 of the Dry Method Apply the fabric before the first coat reaches its final cure phase 9 4 6 Epoxy barrier coating The object of final coating is to build up an epoxy coating that provides an effective moisture barrier and a smooth base for final finishing Apply a minimum of two coats of WEST SYSTEM epoxy for an effective moisture barrier Apply three coats if sanding is to be done Moisture protection will increase with additional coats up to six coats or about a 20 mil thickness Additives or pigments should not be added to the first coat Mixing thinne
43. al try to purchase the same material used by the builder If that is impossible locate a material as close as possible to the core s original thick ness and density It is better to have a slightly thinner core material than a thicker one If the damaged area is smaller than about 2 x 2 Scm x Scm the area may be filled with a thick epoxy 404 or 406 filler mixture If the damaged area is smaller than about 12 x 12 30cm X 30cm and the original core mate rial is not available you may substitute core material cut from soft woods like pine fir or cedar Cut short blocks to the length of the appropriate core thickness For example standard fir 2 x s cut to 1 2 12 7mm lengths will yield 112 x 3 3 8cm X 8 9cm end grained blocks that may be trimmed to fit like tiles in place of damaged 1 2 core Bond the new core material in place Wet out the bonding surfaces of the skin existing core and new core with epoxy Coat the bonding surfaces with an epoxy 406 filler mixture thickened to the consistency of mayonnaise Apply enough thickened epoxy to bridge all gaps between the skin and core and between pieces of core Press the core material firmly in position A small amount of thickened epoxy should squeeze from the joint around the piece Clamp the piece or pieces with plastic covered weights or braces if necessary to hold it in place Smooth the epoxy at the joint and remove excess epoxy before it begins to gel Allow the
44. ally the thinner the paint the finer the grit of the final sanding You must remove all glossiness from the surface Polyurethanes tend to highlight any surface imperfections rather than hide them Check for nicks dings or gouges and repair them as described previously After all repairs have been made wash the entire painting surface with the paint manufacturer s recommended solvent Follow the manufacturer s mixing and application instructions to the letter It s far better to apply two or three thin coats than one thick coat E Repairing Stringers and Floor 10 3 Repairing Stringers and Floor Reinforcing to Improve Panel Stiffness Fixing damaged or delaminated stringers is one of the most common repairs associated with fi berglass boats The usual causes of stringer failure are disintegration of the stringer core mate rial impact damage from slamming and grounding and fatigue from normal use Although each repair situation has its own unique problems the following techniques are fundamental to stringer repair These guidelines will help you repair almost any damaged stringer 3 0 1 Typical stringer construction Stringers are support members bonded into boat hulls usually oriented parallel to the long axis of a boat hull Floors are support members oriented perpendicular to the long axis of the hull They are there for a variety of reasons They stiffen unsupported flatter hull panels in the same way that ribs or beams are used
45. ally stabilizes the surface and prevents oxidation allowing time for coating or bonding The WEST SYSTEM 860 Aluminum Etch Kit contains complete instruc tions 7 2 1 Through bolted fasteners cored panels Hardware bolted through a balsa or foam cored panel can be over tightened or loaded enough to crush the skins and core material Replacing the core with an epoxy mixture in the immediate area of the hardware installation will allow the panel to withstand the compression loads ex erted by the fitting s through bolts and nuts Replacing a portion of the core with epoxy will also provide for better load distribution and protect the core from moisture It will be helpful to have a helper on the opposite side of the panel to handle nuts backing plates and washers and to control excess epoxy If the hardware is through bolted to a cored panel prepare the panel and bond the hardware for increased load transfer as follows Remove the loose hardware and thoroughly clean dirt paint sealants etc from the hardware and the deck or hull surface Wipe both surfaces with solvent to remove any residue or contami nants Inspect for delamination or core damage and make the necessary core repairs before reat taching hardware see Section 5 Cover interior areas below the hardware location with plastic for protection from spills and dirt Clean out the fastener holes and remove a portion of the core around the hole Re drill holes with an overs
46. and the strength to weight ratio of the laminate Although it s not often associated with fiberglass boats wood is used extensively in fiberglass boat construction for primary and secondary structural members like bulkheads frames and stringers core material blocking and trim Stringers bulkheads and other interior fixtures are bonded in after the shell is laid up Many fiberglass boat repairs involve wood and the problems associated with using polyester resins to bond to wood Terminology used to describe the structure of fiberglass boats is not always the same terminol ogy used to describe wooden boats Where fiberglass boat components serve the same functions as wooden boat components their names are often the same However materials and manu facturing methods vary from small boat to large boat from power to sail and from manufac turer to manufacturer Here is a general guide to the fiberglass boat terminology used in this manual Figure 1 3 Bulkhead Cabin top Deck Toe rail Bulkhead T Deck Is al i ma Rub rail Ji Rub rail Cabin liner Cockpit sole Hull Tabbing cored laminate Hull D Cabin sole solid laminate yr Stringer T Keel bolt Strake Keel boss Floor Stringer Keel external ballast Keel Figure 1 3 Components of typical fiberglass sail and power boats 1 1 5 Hydrolysis and gelcoat blisters The repair procedures in this manual address problems most often associated with mech
47. anical damage abrasion bending fatigue impacts and the resulting water damage to cores or other structural components Another type of damage common to fiberglass boats is chemical in na ture Hydrolysis and its symptom gelcoat blisters is a widespread and growing problem in the fiberglass boat world Hydrolysis is more than a cosmetic problem Water soluble materials in a polyester resin lami nate mix with moisture that has penetrated the laminate to create an acidic fluid The fluid col lects in cavities under the gelcoat layer to form blisters This acidic mixture also attacks the polyester resin severing the chemical bonds that hold the resin matrix together as well as the resin to fiber bonds Once hydrolysis has started in a polyester hull the hull s strength has been compromised and the potential for serious additional hydrolysis will never go away If you own a fiberglass boat built with polyester resin you should be aware that the potential for this problem is high especially in warmer climates Any damage due to hydrolysis should be in cluded in an assessment of a boat s condition before repairs are made Although the subject is Introduction 4 too large to be adequately addressed in this manual hydrolysis and gelcoat blisters can be treated with WEST SYSTEM epoxy to limit further damage and in many cases restore a hull s structural integrity For more information about hydrolysis and gelcoat blisters refer to 002 650 G
48. ardware in position brace or weight the hard ware until a small amount of epoxy squeezes from the joint Be sure the fasteners are pushed tight against the hardware 9 Clean the excess epoxy mixture that has squeezed out of the joint and remove the masking be fore the epoxy begins to gel 10 Allow the epoxy to cure at least 24 hours before applying a load to the hardware Allow more time in cool weather 7 3 Casting epoxy bases for hardware Occasionally fittings must be set at specific angles to the hull or deck surfaces Downrigger bases lifeline stanchions winches and turning blocks are all good examples Traditionally hand carved wedge shaped shims have been used to achieve the proper angles with such fit tings Unfortunately wooden shims require a great deal of time and carpentry skill Hardware casting can save time and is easy to do more importantly it can result in a stronger water proof base Cast the hardware at an angle to the surface as follows 1 Prepare the bonding surfaces Clean the substrate and hardware bonding surfaces with solvent to remove any contaminants Sand the deck with 50 grit sandpaper Apply a release agent such as an automobile wax or a nonstick cooking spray to the base of the hardware 53 Installing A Epoxy 406 mixture Temporary spacer Hardware Epoxy interface WINCH ASSEMBLED Cast base Backer plate if deck is thin Shape epoxy mixture fair with deck
49. area and a stan oxy squeezes out of the joint dard sized pilot hole at the bottom of the oversized hole to provide holding power for the fastener to clamp the hardware Sand the contact surface of the hardware item with coarse sandpaper to expose fresh metal Mask off the area not to be bonded on the hardware item to prevent contamination 6 Wet out the deck surface the inside of the fastener holes the fastener threads and the sanded contact surface of the hardware with epoxy While the hardware contact surface is still wet abrade the coated surface with coarse sandpaper working the epoxy into the metal surface This technique exposes fresh metal directly to the epoxy without any air contact and the possi bility of oxidation The 860 Aluminum Etch Kit can be used to treat aluminum fittings before they are wet out 7 Apply an epoxy 404 or 406 filler mixture thickened to a peanut butter consistency to one of the bonding surfaces Apply enough of the mixture to bridge any gaps between the two surfaces Inject or use a mixing stick to fill the fastener s holes with the thickened mixture Use enough mixture so there will be no voids in the hole after inserting the fastener Coat the fastener threads with the thickened mixture 8 Place the hardware item in position Insert and tighten the fasteners until a small amount of ep oxy squeezes out of the joint Do not over tighten Figure 7 6 If you are not relying on the screws to clamp the h
50. asoned Ideal moisture content is 6 to 14 A laminating jig will allow you to laminate a new frame in the controlled environment of your shop Use cardboard or other convenient material to pattern the inside face of the panel at the 19 Repairing Stringers and Floor stringer locations Transfer the pattern line to a laminating jig of one the types illustrated Fig ure 3 8 Laminate frames in a jig as follows Prepare the jig and the strips as suggested Go through a dry run to be sure the strips bend enough and that your jig and clamps can handle the bending of all of the strips Cover the jig with plastic to prevent the frame from bonding to the jig Wet out the strips on both sides with epoxy except for the outer faces of the top and bottom strip Apply thickened epoxy to one side of each strip and stack it in place on the jig against the previ ously coated strip Thicken the mixture with 406 filler to a catsup consistency Be sure that one side coated with thickened epoxy faces each joint p mi 4 lt eA p z Epoxy should squeeze from the joints Use plastic to avoid bonding to jig clamps or work surface Figure 3 8 Transfer the desired stringer profile to a laminat Figure 3 9 Clamp the appropriate number of coated strips ing jig into the jig Trim the stringer to size after the epoxy is fully 4 Clamp the strips to the jig until the epoxy cures Figure 3 9 Use clamps wedges
51. at and allow moisture to escape When the core is dry epoxy is injected under the skin and the skin and core are clamped together until the epoxy cures This method is useful if the delamination is small and is not under an area of non skid deck 1 Drill 6 42 Smm diameter holes at 1 2 5cm intervals creating a pegboard like pattern that extends several inches beyond the delaminated area Figure 5 2 The holes should pene trate the fiberglass skin and the core without drilling into the opposite skin Use a drill depth control device to prevent drilling entirely through the panel Figure 5 2 Drill a pattern of holes 1 apart over the area of delamination to allow the core material to dry out 2 Dry the core thoroughly If the core is extremely wet start by using a high powered shop vac uum cleaner or vacuum bagging to draw water out of the laminate A heat lamp or radiant heater with some air movement over the area will speed the drying CAUTION to be sure the fiberglass surface or the core is not damaged by excessive heat do not heat the surface above 130 F 54 C Proper drying may take days rather than hours Allow the surface and core to cool to room temperature before continuing Occasionally drill a few test holes between the ex isting holes to check for core dryness 3 Cut 1 28mm from the tip of a 807 Syringe Cut the tip at an angle Fill the syringe with an epoxy 404 or 406 filler mixture thickened to the con
52. ately the size shape and depth of the hole Figure 4 7 4 Wet out and apply a layer of thickened epoxy to the beveled edge of the hole and to the backing piece to fill voids and provide good contact between the surface and the first layer of cloth Thicken the mixture with 404 or 406 filler to the consistency of catsup and apply it with a dis posable brush E ae 12 to 1 beveled ANN Ry i een PL aE cavity Y Wi Figure 4 7 Build up a plug of wet out fabric approximately Figure 4 8 Press the wet out patch release fabric and plastic the size shape and depth of the hole into the beveled hole cavity Squeegee over the patch to re move excess epoxy and trapped air 5 Lift the wet out patch release fabric and plastic from the work surface and press it plastic side out into the beveled hole cavity Figure 4 8 Squeegee over the plastic with firm pressure to re move excess epoxy and trapped air and smooth the patch Before the epoxy cures remove the excess from the surrounding areas with a beveled mixing stick or paper towel 6 Allow the patch to cure thoroughly and remove the release fabric Sand to remove any high spots Fair the repair as described in Section 9 4 4 Using WEST SYSTEM Epoxy Finish the repair as described in Section 2 2 27 Repairing Damaged Skins 4 3 3 Vacuum bagging Vacuum bagging is a clamping method that uses atmospheric pressure to apply even clamping pressure to a laminate or in this case
53. ating at a warmer temperature 2 Warm the resin and hardener before mixing to speed the cure in cool weather 3 Switch to a faster hardener if possible See 9 3 2 Under standing and controlling cure time 1 Add more filler to the mixture until it reaches a peanut butter consistency the more filler added the stiffer and easier it will be to sand 2 Allow the wet out coat to gel before applying the fairing material to vertical surfaces See 9 4 4 Fairing Allow the final epoxy coat to cure thoroughly Allow sev eral days if necessary for slow hardeners at cooler tem peratures Apply moderate heat to complete the cure if necessary See 9 3 2 Understanding and controlling cure time 1 Use a different type of paint Some paints and varnishes may be incompatible with some hardeners If unsure test for compatibility on a coated piece of scrap material 2 Use 207 Hardener It is compatible with most paints and varnishes Remove the amine blush and sand the surface thoroughly before applying paints or varnishes See 9 4 7 Final surface preparation 1 Mix smaller batches 2 Transfer the mixture to a container with more surface area immediately after mixing See Understanding cure time Use 206 Slow or 209 Extra Slow Hardener in very warm weather Apply thick areas of fill in several thin layers 1 Coat the surface as the material s temperature is drop ping after warming with heaters or during the later pa
54. ating loads are concentrated on the skin and core the core is crushed and cracks develop in the skin Moisture penetrates the plywood core lead ing to delamination and eventual rot Moisture can also penetrate the transom skin at hardware fasteners and around drain holes and I O cutouts All of these factors have a cumulative effect on structural failure Excessive motor movement may be your first sign of trouble Tap around the suspected area lightly with a small hard object to help reveal any areas of delamination A void under the skin will sound flat or dull compared to a more resonant sound of a solid laminate Damage can be confirmed by drilling 6 42 5mm diameter inspection holes into the core at the suspected delamination Examine the core material removed by the drill for signs of water or decay 5 3 1 Planning the repair The objective is to remove and replace the damaged core Access to the damaged core is gained by removing the fiberglass skin from either the outside or if possible the inside of the transom The boat s design determines which method is more practical Interior access requires much less cosmetic finishing but stringers soles or decks often make interior skin removal impossible The following method describes accessing and removing the core from the outside If the re moved fiberglass skin is in good condition it is usually glued back in place over the new core then structurally and cosmetically blend
55. ave yet to experi ence a cold weather curing problem with WEST SYSTEM epoxy 82 1 Use WEST SYSTEM 205 Fast Hardener WEST SYSTEM 205 Hardener has been designed with a chemically activated polyamine system which exhibits a good cure as low as 35 F 1 5 C It exhibits a faster cure characteristic than 206 Slow Hardener and offers less uncured exposure time which reduces the chances of incom plete cure due to cold temperatures 2 Dispense resin and hardener in the proper mixing ratio All epoxies have been formulated for a specific mixing ratio of resin to hardener It is important to mix your epoxy in the precise ratio recommended by the manufacturer Increasing the amount of hardener will not accelerate cure but it will seriously compromise the epoxy s ulti mate strength WEST SYSTEM Mini Pumps are designed and calibrated to dispense the correct ratio with one pump stroke of resin for every one pump stroke of hardener 3 Warm resin and hardener before using As we discussed above the warmer the resin and hardener the lower the viscosity Thinner resin and hardener will flow through mechanical pumps better cling less to containers and mix ing equipment and exhibit superior handling and wet out characteristics The epoxy can be warmed using heat lamps or can simply be kept in a warm area until you are ready to use it An other simple method of warming the resin and hardener is to construct a small hot box out of rigid sheets of foil ba
56. brace the core in position until the epoxy cures Use only enough clamping pressure to restrict movement and squeeze out some of the mixture Remove the excess thickened epoxy or use it to fill any voids in the joint before it begins to gel Align the core in the exact position of the old core and allow the epoxy to cure thoroughly before removing clamps re bond reusable skins as described below Section 5 3 5 or laminate new skins following the procedures in Section 5 3 6 5 4 Repairing holed panels Minor impacts or abrasions can include dropping a cooler or sharp tool on the deck rubbing against a dock or the weight of an outboard motor mount against a transom This type of dam age often results in a hole or crack through one skin and possible skin delamination around the impact If the damaged area has been submerged or left unprotected for a period of time water penetration can lead to further delamination and eventually rot Most minor impact damage can be repaired with procedures previously described Major impact damage is often associated with collisions groundings natural disasters and oc casionally traffic accidents The amount of damage depends on the force of the impact and the Repairing Core Related Damage 40 shape of the object being hit In this case we are referring to structural damage through the core and both skins Damage may mean a fracture that results in loss of skin continuity or a hole sev eral feet across
57. cedure may result in a weakened structure making it necessary to bond several layers of 6 oz 203g sq m fiberglass fabric over the repair area Refer to Section 9 4 6 Applying fiberglass cloth and tape Skin removal method This method involves removal of a section of skin to expose the core for drying Because of the difficulty or impossibility of fairing and finishing a non skid surface it s often easier to cut and remove an entire non skid area After the core is dried the skin is re bonded and then patched and refinished at the smooth areas outside of the nonskid Follow the procedure in Section 5 2 Replacing damaged cores 5 2 Replacing damaged cores This method is used when the core is damaged and must be replaced or when a skin delamination is in a non skid area of a deck After the core is replaced or dried the skin is re bonded to the core anda repair patch is laminated over the joint to restore skin continuity Remove the skin and replace the damaged core as follows 1 Cut through the skin around the area of delamination with a panel or circular saw with a carbide tipped plywood blade or a router with a small diameter straight fluted bit Set the blade or bit to the depth of the skin only On smooth surfaces cut several inches outside the area of delamination If the delamination is in an area of non skid cut in the smooth area several inches outside of the non skid area or midway between non skid areas 2 Remove the s
58. ches its final cure Apply each coat before the previous coat reaches its final cure and allow the final coat to cure thoroughly Note The final two or three coats may be tinted with WEST SYSTEM 501 white or 503 gray pigment or with 420 Aluminum Powder gray or 423 Graphite Powder black Repairing Stringers and Floor 18 If you desire a smoother cosmetic finish the lay up may be faired and finished Follow the fair ing instructions in Section 9 4 5 Using WEST SYSTEM Epoxy and the finishing instructions in Section 2 Note Vacuum bagging is an ideal clamping method for large bonding areas such as this Refer to 002 150 Vacuum Bagging Techniques published by West System for detailed in formation on vacuum bagging 3 5 3 Reinforcing with stringers One of the advantages of using wood for stringers is that most of the stiffness comes from the wood itself so you need to rely less on additional fiberglass fabric for strength Solid wood and plywood Plywood or solid wood stringers can be cut to shape with a band or table saw The end of each stringer should either butt into a bulkhead or a floor or should be tapered to the surface with at least a 4 to 1 slope Failure to do this will result in hard spots causing stress fractures or cracking The stringer cross sections are generally rectangular or square although a trapezoid is a good selection if you are using solid wood The trapezoid has a wide base for load distribution nar ro
59. ck base area Reapply mold release to the hardware base At this time mask off areas of the hard ware that you don t want to come in contact with the epoxy You may also find it helpful to place small pieces of tape over the holes in the hardware item to prevent the epoxy mixture from oozing up through them when the piece is repositioned Apply enough epoxy 404 mixture thickened to a peanut butter consistency to fill the entire base area If the base to be cast is more than 1 2 12mm thick use 206 Slow Hardener to reduce the possibility of exothermic heat buildup during the curing process Build up the mixture slightly taller than the base supports roughly forming the shape of the base Fill all voids around the epoxy supports Reset the hardware in its proper location Slowly press it into the proper position on top of the cast epoxy supports Allow excess epoxy mixture to squeeze out of the gap between the base of the hardware and the deck Sculpt the squeezed out mixture into the desired shape Figure 7 7b A standard fillet works well in this situation Section 9 4 3 Add extra mixture if neces sary for shaping or to fill any voids Remove any excess epoxy before it cures Allow the epoxy to cure thoroughly Installing Hardware 54 9 Tap the hardware with a mallet to remove it from the base Clean the bottom of the hardware and the top of the cast base with solvent to remove the mold release Sand both bonding surfaces w
60. cked insulation Place a regular light bulb or an electric heating pad inside to maintain a temperature of no greater than 90 F 32 C 4 Stir the resin and hardener thoroughly Use extra care when mixing the resin and hardener and mix for longer than normal periods of time Scrape the sides and bottom of the mixing container using a flat ended mixing stick to reach the corners Using a smaller diameter mixing pot will also improve the chemical activity because the limited surface area will not dissipate heat produced by the reaction 5 Warm working surfaces Applying warmed epoxy to a cold structure will quickly retard the molecular bonding activity of the epoxy Be certain the structure as well as the area surrounding the structure is brought up to temperature A hull for example which is colder than the surrounding air may experi ence condensation and result in water contamination to epoxy applied on it Warm the struc ture as much as possible This can be done by constructing tents around small areas and heating with portable heaters or warming the area with hot air guns or heat lamps Small components or materials such as fiberglass cloth can be warmed before use in a hot box as described above 6 Prepare surfaces carefully between applications When coating under cold conditions a thin film of epoxy often dissipates any exothermic heat generated by the reaction When heat is dissipated quickly the epoxy may not cure for an ex tend
61. clamping Cure time dictates how long you must wait before removing clamps or before you can sand or go on to the next step in the project Two factors determine an epoxy mixture s open time and overall cure time hardener cure speed and epoxy temperature Hardener speed Each hardener has an ideal temperature cure range Figure 9 1 At any given temperature each resin hardener combination will go through the same cure stages but at different rates Select the hardener that gives you adequate working time for the job you are doing at the temperature and conditions you are working under The product guide and container labels describe hard ener pot lives and cure times Pot life is a term used to compare the cure speeds of different hardeners It is the amount of time a specific mass of mixed resin and hardener remains a liquid at a specific temperature A 100g mass mixture in a standard container at 72 F Because pot life is a measure of the cure speed of a specific contained mass volume of epoxy rather than a thin film a hardener s pot life is much shorter than its open time Epoxy temperature The warmer the temperature of curing epoxy the faster it cures Figure 9 3 Curing epoxy s temperature is determined by the ambient temperature plus the exothermic heat generated by its cure Ambient temperature is the temperature of the air or material in contact with the epoxy Air temperature is most often the ambient temperature unless
62. ctive of the repair procedures in this section is to restore skin continuity by re building the load carrying ability of the fibers through the damaged area of the skin The repair procedures for cores and core related damage are discussed in Section 4 Typical fiberglass skin Below an outer layer of gelcoat and chopped strand mat a typical fiberglass skin is comprised of alternating layers of woven roving and more chopped strand mat repeated until a required thickness is reached In a cored panel the schedule is similar but the inner and outer skin are generally much thinner than a single non cored panel Figure 1 1 Some of the newer struc tures being manufactured today may include layers of unidirectional or multidirectional glass aramid or graphite fibers The fabric is usually bonded together with an isophthalic or orthophthalic polyester resin although vinylester resins are being used more frequently in place of polyester resins Restoring skin continuity Skin continuity can be restored if enough fibers can be bonded across a damaged area to equal the strength of those that were damaged or removed The lay up schedule for your repair work should duplicate thickness and types of materials used in that area as closely as possible How ever heavy woven roving may be replaced by more layers of lighter weight woven or bidirectional fabrics Although more layers may mean extra work lighter weight fabrics are of ten easier to find and
63. ding can be used when joints have minimal loads and excess absorption into porous surfaces is not a problem Before mixing epoxy check all parts to be bonded for proper fit and surface preparation 9 4 1 Surface preparation gather all the clamps and tools necessary for the operation and cover any areas that need protection from spills Two step bonding 1 Wet out bonding surfaces Apply a straight resin hardener mixture without fillers to the sur faces to be joined Figure 9 8 Wet out small or tight areas with a disposable brush Wet out larger areas with a foam roller or by spreading the resin hardener mixture evenly over the sur face with a plastic spreader You may proceed with step two immediately or any time before the wet out coat becomes completely tack free Figure 9 9 Apply enough thickened epoxy to one of ened epoxy for maximum penetration and greater the bonding surfaces so that a small amount will adhesion squeeze out of the joint when clamped with moder ate pressure 71 Using WEST SYSTEM Epoxy 2 Apply thickened epoxy to one bonding surface Modify the resin hardener mixture by stirring in the appropriate filler until it becomes thick enough to bridge any gaps between the mating surfaces and to prevent resin starved joints Apply enough of the mixture to one of the sur faces so that a small amount will squeeze out when the surfaces are joined together with a force equivalent to a firm hand grip Fi
64. e panel after the damage has been repaired as outlined in Section 3 1 Remove all of the damaged material Use a grinder to cut down to solid laminate or a saw to en large a hole to solid undamaged laminate While you re removing the damaged material try to maintain a circular or oval shape The laminate around an impact site may be structurally dam aged beyond the area of visible damage Tap around the damaged area with a small hammer or metal object Soft or dull sounding areas indicate a void or fracture under the surface that should be exposed y Figure 4 1 Grind a S minimum 12 to 1 bevel W E around the edge of the N EF excavated hole whether TRN the damage extends par Cia RN tially or completely X px X through the skin 7 2 Grind a bevel around the edge of the repair area to create a bonding area for the patch that will keep the patch flush with the skin s surface A minimum 12 to 1 bevel is required to assure the transfer of loads across the repair area Figure 4 1 For example if you are left with a hole through a 1 4 6mm thick laminate the outer edge of the bevel will extend 3 75mm from the inside edge of the hole If the skin is very thin a longer bevel angle is required Proceed with the laminating of the repair patch as described in Section 4 3 if a you have reached solid undamaged laminate without grinding through the skin b the hole through the skin of a non cored panel
65. e squeezing just a little of the mixture from the joint Use braces and wedges to clamp the core in position Try to achieve uniform clamping pressure and avoid any gaps between the core and the panel Shape the excess epoxy mixture into a fillet at the core panel joint before it hardens Allow the epoxy to cure before removing clamping Bond the fiberglass fabric to the core and panel as follows Wet out the bonding surface of the core material and panel with a mixture of resin hardener Squeegee a thin layer of thickened epoxy over the core and exposed panel bonding area if the surface is heavily textured Thicken the epoxy with 404 or 406 filler to the consistency of may onnaise The thickened epoxy will fill voids on the surface and provide better contact with the first layer of cloth Center the largest piece of fiberglass fabric over the reinforcement area and wet it out with ep oxy You may find it helpful to hold the fabric in place with pieces of masking tape Squeegee any excess epoxy from the surface but make sure the entire piece of cloth has been saturated Apply each successive piece of cloth in the same manner Each piece may be applied immedi ately after the previous piece is applied or any time before the previous piece reaches its final cure The final piece should extend beyond the core at least 2 on each side Allow the lay up to reach its initial cure Apply two or three coats of epoxy before the lay up rea
66. e 4 6 Before the ep oxy cures remove the excess from the surrounding areas with a beveled mixing stick or paper towel Allow the patch to cure thoroughly Remove the release fabric Release fabric will not bond to the epoxy and will leave a smooth tex tured surface Sand to remove any high spots Fair the repair as described in Section 9 4 4 Fin ish the repair as described in Section 2 2 4 3 2 Small area patch If the patch area is smaller than about 8 20cm on a side it may be easier to prepare the entire patch first on a piece of plastic placed on a flat surface The patch can then be bonded into the hole cavity in one operation 1 Cut an appropriate number of pieces of fiberglass fabric the same shape as the hole The first piece should match the outside edge of the bevel with subsequent pieces gradually getting smaller The final layer should match the inside edge of the bevel The combined thickness of the layers should be slightly thinner than the original panel to allow for shaping and fairing 2 Cuta piece of plastic and a piece of release fabric several inches larger than the patch area Place the plastic on the working surface followed by the release fabric 3 Wet out each piece of fabric with epoxy and stack the fiberglass cloth pieces on the working sur face beginning with the smallest piece and finishing with the largest Center each layer over the previous layer You will end up with a plug of wet out fabric approxim
67. e any dust or loose material 2 Wet out the repair area with a resin hardener mixture Fill the void with an epoxy 404 or 406 mixture thickened to the consistency of peanut butter Use a plastic spreader to shape the mixture to match the surface contour Leave the mixture slightly higher than the surrounding area and remove any excess before it begins to cure Allow the epoxy to cure thoroughly Sand the area to blend with the surrounding contour Use 50 grit paper to remove any bumps or ridges and finish with 80 grit paper when you are close to the final shape Fill any remaining voids if necessary repeating Steps 3 and 4 Apply two or three very thin coats of epoxy to seal the surface Extend each coat slightly beyond the previous one to feather the edge The area may be warmed with a heat lamp to speed the cure and to help the epoxy flow out Allow the final coat to cure thoroughly Wet sand the area with 180 grit paper to prepare for the final finish 8 Finish the area with paint or the gelcoat finishing procedure Section 2 2 1 beginning with step 4 Reinforce the laminate as necessary to reduce flexing following the procedure in Section 3 2 2 Finishing Although many types of coating systems are compatible with WEST SYSTEM epoxy and provide the necessary UV protection we recommend polyester gelcoat for small repair areas and linear polyurethane paint for large repairs Although gelcoat may be used over large
68. e clamped in position you shape it into a fillet For larger fillets add thickened mixture to the joint as soon as the bonding operation is complete before the bonding mixture is fully cured or any time after the final cure and sanding of exposed epoxy in the fillet area 1 Bond parts as described in Section 9 4 2 2 Shape and smooth the squeezed out thick epoxy into a fillet by drawing a rounded filleting tool mixing stick along the joint dragging excess material ahead of the tool and leaving a smooth cove shaped fillet bordered on each side by a clean margin Some excess filleting material will remain outside of the margin Figure 9 12 Use the excess material to refill any voids Smooth the fillet until you are satisfied with its appearance A mixing stick will leave a fillet with about a radius For larger fillets an 808 Plastic Squeegee cut to shape or bent to the desired radius works well Figure 9 12 Shape and smooth the fillet with a Figure 9 13 Clean up remaining excess epoxy out rounded tool side of the clean margin before it cures Apply additional thickened epoxy to fill voids or make larger fillets Apply the mixture along the joint line with the rounded mixing stick using enough mixture to create the desired size of fillet For longer or multiple fillets empty caulking gun cartridges or disposable cake decorating bags can be used Cut the plastic tip to lay a bead of thickened epoxy large enough for the de sired
69. e edge of the bevel should be short of the corner as described earlier in Section 5 3 1 Planning the repair 2 Cut the appropriate number of fabric pieces to the size and shape of the transom Cut the first piece 1 2 from the outer edges of the bevel Cut each of the remaining pieces smaller on each side than the piece below it The final piece should be the same size as the inner edge of the bevel The edges of the middle pieces should be evenly spaced between the edges of the first and last pieces The spacing depends on the number of pieces equaling the laminate thickness and the length of the bevel 3 Wet out the transom core and bevel with epoxy Using a plastic spreader coat the transom core with a thin even layer of an epoxy 406 filler mixture thickened to a mayonnaise consistency 4 Wet out the cloth with epoxy ona work surface covered with plastic sheeting Apply enough ep oxy to saturate the cloth using a thin foam roller or by pouring epoxy onto the fabric and spreading with a plastic spreader 5 Place the fabric on the transom centering it within the edges of the bevel Smooth the fabric into the thickened epoxy layer with a plastic spreader Use the spreader to remove trapped air and excess epoxy and to smooth the fabric against the surface Figure 5 12 Wet out and apply each layer of fabric New laminated with epoxy ending with the plywood core smallest piece Smooth each layer with a plastic spreader to remove w
70. e epoxy to cure thoroughly before removing vacuum pressure or clamps Grind a 12 to 1 bevel on both edges of the joint and laminate a repair patch over the joint to re store skin continuity Figure 5 7 The bevel will provide a recessed bonding area for the appli cation of fiberglass fabric and allow the patch to be faired flush with the surface The objective and procedure for patching the joint are the same as repairing damaged skins Follow the proce dure described in Section 4 3 Replace damaged core from below A variation of this technique is to replace damaged core by removing the lower or inside skin and leaving the outer skin intact Although working overhead makes this variation more diffi cult the difficulty is offset by the elimination the cosmetic work Step 4 above that would be required on the outside of the deck This variation is especially useful when the repair is in a non skid area of the deck The underside of a deck is often covered by a fabric liner which can be peeled back to expose the repair area and then put back in place hiding the repair After removing the skin and the damaged core replace the core as described above Except cut the core into convenient sizes for working overhead and use epoxy thickened enough to hold the pieces in place overhead Immediately bond the inner skin to the core and as necessary use sticks to prop the entire re pair in place flush with the surrounding skin until cured Whe
71. e profiles from the root midpoint and tip of the keel to 1 2 12mm A C grade plywood Mark the Plywood template centerlines on the E E c3 keel and on the tem plates Ee Waterline ROOT MIDPOINT TIP gs and transfer the profiles to 1 2 12mm A C grade plywood Figure 8 5 Cut out the three tem plates with a band saw or saber saw Sand the edges of the foil shape carefully to eliminate any bumps or unfairness Mark the keel s centerline on each end of the template Seal the profile edge of the templates with a coat of epoxy and sand them smooth after the epoxy cures Prepare the area for bonding Remove all paint Wire brush the entire surface of external keels to remove any contamination and to expose fresh iron or lead Be sure to wear an appropriate dust mask especially when sanding or wire brushing lead Sand the surface of internal keels or hulls to remove loose fillers and gelcoat and expose solid fiberglass laminate Dry the keel using a hot air gun hair dryer or heat lamp Locate and mark the centerline on the leading edge and if necessary the trailing edge of the keel Mark the template locations on both sides of the keel Check the keel s profile with the templates to locate any high spots and to gauge how much fairing compound to apply to the low areas Grind down or plane off excessive high spots Wet out 2 3 wide strips at the template locations with epoxy If
72. e repair patch this backing method provides a good air tight seal and should be used even if you have access to the back of the panel Be sure to fill the screw holes with thickened epoxy before laminating the patch Refer to Section 4 3 3 for information on vacuum bagging for repair 4 3 Laminating a repair patch The new skin must be laminated to approximately the same thickness to assure the strength of the original skin Multiple layers of lightweight cloth will develop the same or greater strength than a single layer of heavy cloth The patch can be laminated by either of two methods depending on the size of the patch For large areas it s easier to handle and lay up each piece of cloth one piece at a time For smaller areas it may be more convenient to wet out and lay up all of the pieces together 4 3 1 Large area patch 1 Cut an appropriate number of pieces of fiberglass fabric the same shape as the hole The first piece should match the outside edge of the bevel with subsequent pieces gradually getting smaller The final layer should match the inside edge of the bevel at the hole The combined thickness of the layers should be slightly thinner than the original panel to allow for shaping and fairing Figure 4 5 Wet out and apply a layer of thickened epoxy to the beveled edge of the hole and to the backing piece to fill voids and provide good contact between the surface and the first layer of cloth Thicken the mixture with 404
73. e teak are smooth sand them with 50 grit sandpaper Wipe the bonding surfaces of the teak strips using paper towels with acetone or lacquer thinner 30 minutes before bonding This will help to improve epoxy penetration by removing some of the natural oil from the surface of the teak 3 Place the first set of teak strips in the desired location and mark the bonding area and reference location points on the strips and deck Place only the number of strips that can be applied during the open time of a batch of epoxy The open time will vary with the resin hardener combination you are using and the ambient temperature Begin with a small area or number of strips 4 Wet out the bonding surface of the first set of teak strips and the corresponding bonding area of the deck Remember to solvent wipe the bonding surfaces of the teak 30 minutes before the wet out Apply a heavy layer of thickened epoxy to the wet out deck surface Thicken the resin hardener mixture to a mayonnaise consistency with 404 High Density filler Then add enough 423 Graphite Powder to turn the mixture to an opaque black color Apply enough thickened epoxy to bridge gaps between the strips and the deck and to squeeze up and fill the gap between the planks A 809 Notched Spreader works well to apply an even layer over the deck Be sure to leave reference marks uncovered 5 Position the first set of strips on the deck Use the reference marks as necessary Repairing and Upgrading
74. e to leave enough epoxy to be absorbed by both the cloth and the surface below it Try to limit the amount of squeegeeing you do The more you work the wet surface the more minute air bubbles are placed in suspension in the epoxy This is especially important if you plan to use a clear finish see below You may use a roller or brush to apply epoxy to horizontal as well as vertical surfaces Smooth wrinkles and position the cloth as you work your way to the edges Check for dry areas especially over porous surfaces and re wet them as necessary before proceeding to the next step If you have to cut a pleat or notch in the cloth to lay it flat on a compound curve or corner make the cut with a pair of sharp scissors and overlap the edges for now Note For clear wood finishes an alternative wet out method is to lay the epoxy onto the fabric with a short bristled brush Dip the brush in the epoxy and lay the epoxy on the surface in a light even stroke Don t force the epoxy into the cloth which may trap air in the fabric and show through the clear finish Apply enough epoxy to saturate the fabric and the wood below After several minutes lay on additional epoxy to dry white areas Figure 9 17 Spread the epoxy from the center o Figure 9 18 Squeegee away excess epoxy before the the fabric toward the edges with a plastic spreader first batch begins to gel 75 Using WEST SYSTEM Epoxy 7 Squeegee away excess epoxy before the first ba
75. ear appropriate eye protection skin protection and a dust mask when cutting or grinding fiberglass Follow safety guidelines when handling epoxy Section 9 1 If you have additional questions after reading the Using WEST SYSTEM Epoxy section you may write or call the West System technical staff West System Inc P O Box 665 Bay City MI 48707 866 937 8797 8 00 AM 5 00 PM EST Fax 989 684 1287 www westsystem com E 5 Repairing Minor Cracks and Holes 2 Repairing Minor Cracks and Holes Most of the repair jobs found on fiberglass boats are cosmetic in nature Cracking or crazing of the gelcoat and scrapes and dings account for much of the repair work being done in boat shops Permanent repairs to these types of damage can be made with WEST SYSTEM epoxy When properly applied an epoxy repair affords an extremely durable water resistant repair that of fers an excellent base for various finishes This section addresses the cosmetic repair of minor surface damage and cracking and panel reinforcement to reduce the cause of cracking 2 0 1 Assessing damage Figure 2 1 Typical types of cracks from im pact or flexing The pattern of cracking may help to determine their cause It s easy to account for the scrapes dings and cracks that result from impacts but the causes of flex cracking or crazing may not be as obvious Most cracks or crazing that appear gradually and get worse over time are the result of flexing and are most
76. earing occurs Some alloys are more malleable and easier to forge than others Plane or file the remainder of the bulge flush after you have forged as much as is practical Fig ure 8 3 For small areas a body file works well When greater amounts of lead must be re moved a woodworking plane is the best tool for the job Apply a liberal coat of petroleum jelly to the lead surface Adjust the plane s blade for a medium cut and be certain the blade is sharp Thoroughly clean the lead of any remaining petroleum jelly with solvent after the bulge has been faired When the solvent has evaporated scrub the surface vigorously with a wire brush to expose fresh lead Wet out the repair surface with epoxy Brush the still wet surface with a wire brush to expose fresh lead directly to the epoxy avoiding any air contact and possibility of oxidation Fill the voids with an epoxy 407 low density filler mixture thickened to a peanut butter consis tency Trowel the mixture into the voids and shape it to match the form of the keel Figure 8 4 If the volume of a void is larger than a golf ball apply the mixture in several applications to avoid excessive exothermic heat buildup Allow the mixture to cure thoroughly Figure 8 4 Trowel the epoxy 407 mixture into the voids and shape it to match the form of the lt 2 fe aii IS Epoxy 407 mixture Sand the cured mixture to the shape of the keel with a 50 grit sanding block Fill any
77. ed primarily to provide a form for a struc tural fiberglass skin ACTIVE CORE Solid wood or plywood INACTIVE CORE Low density foam core or no core 11 Repairing Stringers and Floor Occasionally you will find a material that appears to be plywood but all the veneers are ori ented in the same direction You cannot repair this unidirectional material with plywood Ply wood has half the grain running at right angles to the face veneer It does not have the same strength as unidirectional material Acommon example of unidirectional plywood material is called laminated veneer lumber LVL Inactive core stringers rely on the geometry of the fiberglass skins to provide stiffness The nonstructural cores are primarily forms to give a vertical profile to layers of fiberglass Inactive cores are made of low density foam cardboard tube or in the case of molded stringers no core at all Molded stringers are pre built in a mold and tabbed in after the hull is built This type of stringer has no core material just fairly heavy fiberglass skins to stiffen the hull 3 0 2 Assessing damaged stringers Before you start any repair it is a good idea to know what you are getting into Looking at the suspected area of damage may be as easy as opening a hatch but don t count on it Hull liners or cabin and cockpit soles are common and usually fastened to the very stringers you are trying to fix It is also difficult to see under engines water ta
78. ed into the surrounding skin as described in Section 5 2 1 Support the hull to prevent sagging or distortion before removing the skin and core This repair is much easier if the total area affected can be confined to the transom and not ex tend around the corners It is much easier to end a paint job at the corner of an object where there is a visual break than it is to match color and texture in the middle of an area The follow ing transom repair method leaves enough fiberglass around the perimeter of the transom for a proper bevel and repair patch yet allows enough access for the damaged core to be removed and replaced Before making a substantial cut through a structural fiberglass skin support the hull with blocking to maintain the hull s shape Determine the location of the cut After removing the motor hardware and trim measure the fiberglass skin thickness at one of the holes in the transom The fiberglass thickness determines the bevel length and the distance of the cut line in from the corners The bevel length is at least 12 times the fiberglass thickness A 12 to 1 bevel allows room for multiple layers of fiberglass fabric and epoxy across the cut line to restore strength to the fiberglass skin If the fiberglass skin is thick the width of the bevel will be at least 11 If the fiberglass is 1 4 thick the cut line will need to be at least 3 in from the corners to allow for a 3 bevel If the original fiberglass skin i
79. ed period of time Some reaction with water may occur resulting in the formation of an amine blush on the surface Immediately prior to applying subsequent coatings wash the sur face with clean water and allow it to dry thoroughly Cold weather storage It is best to store WEST SYSTEM materials above 35 F 1 5 C with the container caps screwed down tightly Storing epoxy in extreme cold may cause crystallization The formation of crys tals does not compromise the epoxy and they can be remedied Boil water in a pot large enough to hold your epoxy containers Remove each container s lid to avoid pressure build up which may cause the cans to burst and place the cans in the hot water Continually stir the epoxy with a clean stick until the liquid regains clarity and all crystals have melted Remove from the water replace the lids tightly and invert the container to melt any crystals which may be clinging to the top of the container If the resin pump has crystallized pumping warm resin through it should dissolve the crystals W 83 Appendix D Problem solving guide PROBLEM The epoxy mixture has not cured after the recommended cure time has passed Bond failure Clear coating turned cloudy Waxy film appears on surface of cured epoxy The hardener has turned red after long storage This guide is designed to help identify and prevent potential problems associated with epoxy use If the prevention steps described here do n
80. een unthickened epoxy and the three consistencies referred to in this manual Always add fillers in a two step process 1 Mix the desired quantity of resin and hardener thoroughly before adding fillers Begin with a E Figure 9 7 Blend in Ns g small handfuls or Te U m scoops of the appropri wl i ate filler until the de sired consistency is reached small batch allow room for the filler 2 Blend in small handfuls or scoops of the appropriate filler until the desired consistency is reached Figure 9 7 For maximum strength add only enough filler to completely bridge gaps between surfaces without sagging or running out of the joint or gap A small amount should squeeze out of joints when clamped For thick mixtures don t fill the mixing cup more than 1 3 full of epoxy before adding filler When making fairing compounds stir in as much 407 or 410 as you can blend in smoothly for easy sanding the thicker the better Be sure all of the filler is thoroughly blended before the mixture is applied Additives Additives are used to give epoxy additional physical properties when used as a coating Al though additives are blended with mixed epoxy in the same two step process as fillers they are not designed to thicken the epoxy Follow the mixing instructions on the individual additive containers 9 3 5 Removing epoxy Removing uncured or non curing epoxy Removed uncured epoxy as you would spilled resin Scrape as much mate
81. eight gain by applying unidirectional fiberglass or carbon graphite fibers tape along the top side of the stringer facing away from the panel When applied to the top of the stringer where tensile loads 3 are highest all of the fibers can be oriented parallel to the load Carbon fiber is more costly than fiberglass but savings in weight and bulk for the same amount of stiffening may offset carbon s additional cost Refer to Section 9 4 6 Applying Woven Cloth and Tape for application procedures Recommended Reading Upgrading the Cruising Sailboat by Daniel Spurr Seven Seas Press Inc Newport RI an excellent in depth discussion of strengthening the hull and deck m 21 Repairing Damaged Skins 4 Repairing Damaged Skins Cut through a fiberglass boat s hull or deck and you will find either a non cored single skin or a cored laminate two skins sandwiching a lower density core material Often a panel changes from cored to non cored at corners at the ends of panels and at panel openings Depending on the size of the boat and the location of the damage a structural repair could involve either or both types of laminate Whether cored or non cored the structure of a fiberglass boat relies on the continuity of the fi bers that run through its skins Damage from impact abrasion flexing or even deterioration of the resin holding the fibers in place can reduce or eliminate the load carrying ability of these fi bers The obje
82. elcoat Blisters Diagnosis Repair amp Prevention published by West System Inc 1 2 WEST SYSTEM epoxy for fiberglass repair Unsaturated polyester resins perform fairly well during the construction of a structure when all of the layers of resin are applied and allowed to cure together This type of bond is considered a primary bond Problems can occur however when you try to bond polyester resin to a previ ously cured laminate as is necessary in every repair application This type of bond is secondary or post bonding To effectively repair damage typical of fiberglass boats the repair material must be a superior structural adhesive capable of bonding not only to polyester resin but also to glass fiber wood metal and other materials There are several important reasons to use WEST SYSTEM epoxy rather than a polyester resin or other material for fiberglass boat repair Polyester resin can shrink from 5 to 8 creating stress concentrations at the repair joint In addition epoxy is more effective as a moisture bar rier and it forms a superior mechanical bond with the cured polyester and other materials in sec ondary bonding Since epoxy is more durable than polyester the epoxy repair actually may be stronger than the original structure When you consider ease and practicality of application availability safety and access to technical assistance WEST SYSTEM epoxy is an excellent choice for fiberglass boat repair 1 2 1 Using this manual
83. eloped an approach called hardware bonding The principle of hardware bonding is to eliminate all hardware movement by distributing the high single point loads of the hardware to as large an area of deck or hull laminate as possible This is accomplished in two ways by bonding all fas teners into the laminate to equalize their load carrying ability and by bonding the contact sur face of the hardware item to the laminate surface Proper hardware bonding techniques can dramatically improve the hardware s load carrying capacity over hardware installed by stan dard methods Bonded hardware becomes an integral part of a deck or hull and can perform long term without leak causing movement In saltwater applications our experience has been that bonded hardware and fasteners show excellent resistance to corrosion attack Where fasteners are vulnerable to flexure and saltwater attack i e hollow or bridged traveler tracks bonded U bolts or solitary eyebolts a small sili cone sealant fillet covering the joint between the cured epoxy and the fastener will protect against moisture and salt intrusion Of course any exposed metal surface will be subject to the effects of saltwater corrosion therefore proper maintenance and cleaning procedures must be practiced Installing Hardware 48 7 1 Bonding fasteners Bonding fasteners with epoxy is the most important part of hardware bonding and improving hardware load capacity The techniques for bonding fas
84. ent evaporates Scrape out the cracks or scratches with a 90 V shaped scraper to expose clean gelcoat and in crease the bonding area slightly Do not scrape through the gelcoat Fill the scraped out voids with gelcoat Mix a small batch of gelcoat without thinners Trowel the mixture into the voids leaving it slightly higher than the surface Allow the gelcoat mixture to cure thoroughly 10 Repairing Minor Cracks and Holes 8 Apply tape around the perimeter of the de waxed area Mask the area beyond the repair to pro tect the boat from overspray If there is a molded body line or corner near the repair you may want to extend the color patch to that point The same is true for a painted or vinyl stripe Sand the additional area out to the tape line with 320 grit paper This will be the total area to be gelcoated Determine the gelcoat batch size for the size of the repair approximately 80 square feet per gal lon of gelcoat 20 sq ft per qt Tint the batch of gelcoat to match the color of the boat If the boat is fairly new and the manu facturer is still in business you may be able to get gelcoat that will be a very close color match If this is not an option you will need to get the gelcoat from a FRP product supplier Many marine distributors handle the gelcoats from various resin manufacturers You will also need pigments to tint the base color to obtain a good match These pigments are generally available from t
85. epoxy to cure thoroughly before removing clamps 5 2 1 Re bonding the skin If the skin was damaged from an impact or abrasion or damaged during removal laminate a new skin in place against the new core as described in Section 4 3 If the skin is reusable re bond the skin as follows Sand the surface of the core and the inner surface of the skin that was removed Dry fit the skin for fit and to be sure that it lays flat and fair with the adjoining skin Bond the skin to the core in its original position Wet out the bonding surfaces of the core and skin with epoxy Coat the bonding surface of the core with an epoxy 406 filler mixture thick ened to the consistency of mayonnaise Apply enough of the thickened mixture to bridge all gaps between the skin and core Position the skin so that the gap around the piece the saw cut is equal on all sides 33 Repairing Core Related Damage Figure 5 7 Grind a 12 to 1 bevel on the edges of the joint so the joint re pair patch can be faired flush with the surface 12 to 1 bevel Clamp the skin in position with vacuum bagging weights braces or sheet metal screws Vac uum bagging is an ideal method for providing equal clamping pressure over large areas Follow the procedure for vacuum bagging repair patches described in Section 4 3 3 If you are using standard clamping a small amount of epoxy should squeeze from the joint Remove excess ep oxy before it begins to gel Allow th
86. er from exo thermic heat build up DO NOT attempt to alter the cure time by altering the ratio An accurate ratio is essential for a proper cure and full development of physical properties Dispensing with Mini pumps Most problems related to curing of the epoxy can be traced to the wrong ratio of resin and hard ener To simplify metering we recommend using WEST SYSTEM Mini Pumps to dispense the resin and hardener Mini Pumps mount onto the resin and hardener containers and are cali brated to deliver the proper working ratio of resin to hardener 1 stroke 1 stroke Resin Hardener Pump one full pump stroke of resin for each one full pump stroke of hard ener Depress each pump head fully and allow the head to come completely 9 0 back to the top before beginning the next stroke Figure 9 4 Partial strokes will give the wrong ratio Read the pump instructions before using pumps Before you use the first mixture on a project verify the proper ratio according to the instruc tions that come with the pumps Recheck the ratio anytime you experience problems with curing Dispensing without Mini Pumps Weight volume measure 67 Using WEST SYSTEM Epoxy Figure 9 5 Stir resin and hardener together thor oughly at least one minute longer in cooler tem peratures Figure 9 4 Dispense the proper proportions of resin and hardener To measure 105 Resin and 205 or 206 Hardener by weight or volume combine 5 parts resin wit
87. er up the side 3 76mm or so the second layer 3 out on the sole and the third layer centered over the corner This creates an aggregate build up three layers thick on the corner without causing a hard spot at the edges of the tabbing The tape can be applied over the uncured fillet or after it is thoroughly cured and sanded T _ Figure 6 2 Apply fiberglass tape over the fillet Stagger the edges of the tabbing when using multiple layers so they do not end in the same place on the hull side or sole Wet out A fastener holes y gt be oe ns f i i he as s F ra NN 2 r Bed plywood into thick epoxy on stringers floors and cleats 5 Reinstall the carpeting or covering after the epoxy is cured If painting the sole make sure you wet sand the surface to remove all gloss before priming and painting or installing a teak surface When reinstalling seats and deck hardware be sure to seal the fastener holes with epoxy This will prevent the same type of damage from recurring 6 2 Installing a teak deck simply improving the looks and value of a boat The thickness of the teak determines which of two methods are used to install it With both methods the teak is bonded to the substrate with epoxy Bonding with epoxy not only seals the deck with an epoxy moisture barrier but it elimi nates the many fasteners that penetrate conventional teak decks and are often a source of leaks Installing a teak deck
88. ers are labeled with the same Group Size letter A B or C Group Size A B C Resin quantity 105 A 1 qt 94 L 105 B 98 gal 3 74 L 105 C 4 35 gal 16 47 L Hardener quantity 205 A or 206 A 43 pt 20 L 207 A or 209 A 66 pt 31 L 205 B or 206 B 86 gt 81 L 207 B or 209 B 1 32 qt 1 24 L 205 C or 206 C 94 gal 3 58 L 207 C or 209 C 1 45 gal 5 49 L Filler epoxy proportion guide Approximate mixed epoxy required to produce a catsup mayonnaise or peanut butter consis tency for the various sized filler products at 72 F Mixed quantity 1 2 qt 1 15 L 1 3 qt 1 26 L 1 2 gal 4 55 L 1 3 gal 4 98 L 5 29 gal 20 L 5 8 gal 21 9 L Saturation Coat Porous Surfaces 90 105 sq ft 8 5 10m 90 105 sq ft 9 10 m 350 405 sq ft 32 37 m 370 430 sq ft 35 40 m 1530 1785 sq ft 142 165 m 1675 1955 sq ft 155 180 m Build up Coats Non Porous Surfaces 120 135 sq ft 11 12 5 m 120 135 sq ft 11 13 m 462 520 sq ft 43 48 m 490 550 sq ft 45 50 m 2040 2300 sq ft 190 213 m 2235 2520 sq ft 207 233 m Fiberglass thickness per layer Mixtures will be thinner at higher temperatures Filler 403 9 403 28 403 B 404 15 404 45 404 B 405 406 2 406 7 406 B 407 5 407 15 407 B 410 2 410 7 410 B Package size 6 0 oz 20 0 oz 2
89. even clamping pressure over all areas of a panel regardless of the size shape or number of layers For detailed information on vacuum bagging refer to 002 150 Vacuum Bagging Tech niques Clamping Any method of clamping is suitable as long as the parts to be joined are held so that movement will not occur Methods of clamping include spring clamps C clamps and adjustable bar clamps heavy rubber bands cut from inner tubes nylon reinforced packaging tape applying weights and vacuum bagging When placing clamps near epoxy covered areas use polyethyl ene sheeting or peel ply under the clamps so they don t inadvertently bond to the surface Sta ples nails or drywall screws are often used where conventional clamps will not work Any fasteners that need to be left in should be of a non corroding alloy such as bronze In some cases the thickened epoxy or gravity will hold parts in position without clamps 9 4 3 Bonding with fillets A fillet fil it is a cove shaped application of thickened epoxy that bridges an inside corner joint It is excellent for bonding parts because it increases the surface area of the bond and serves as a structural brace All joints that will be covered with fiberglass cloth will require a fillet to support the cloth at the inside corner of the joint The procedure for bonding with fillets is the same as normal bonding except that instead of re moving the squeezed out thickened epoxy after the components ar
90. f and protect strips from rough sawn teak planks surrounding surfaces proves the mechanical bonding characteristics of the strip The remaining marks on the ex posed surfaces will be sanded smooth after the new deck has been laid If you plan to mill your own stock select a plank width that makes the most efficient use of the raw stock Teak is generally available in 2 thick rough sawn planks you should get close toa 134 45mm finished dimension from these planks Saw the stock so that the strips will be edge grained Figure 6 3 This will minimize expansion and contraction of the wood and make a more attractive even wearing surface than will slab grained strips Select wood that is well seasoned Make all necessary repairs to the sole or deck structure before applying teak veneer See Section 6 1 to repair a plywood deck See Section 5 to repair a cored fiberglass laminate deck Install a teak deck as follows 1 Plan the location and pattern for the layout of the teak strips Figure 6 4 Cut the strips to fit and mark them for reference as necessary Mask off the application area and cover the sur rounding area with plastic for protection against spills 2 Prepare the bonding surfaces Wipe the bonding surfaces of the boat with a wax and silicone re mover or solvent and a dry with a paper towel Grind non skid areas flat and abrade smooth surfaces with 50 grit sandpaper Remove sanding dust If any of the bonding surfaces of th
91. face to be bonded is solid Remove any flaking chalking blistering or old coating before sand ing Remove all dust after sanding Special preparation for various materials Cured epoxy Amine blush can appear as a wax like film on cured epoxy surfaces It is a by product of the curing process and may be more noticeable in cool moist conditions Amine blush can clog sandpaper and inhibit subsequent bonding but it can easily be removed It s a good idea to assume it has formed on any cured epoxy surface To remove the blush wash the surface with clean water only not solvent and an abrasive pad such as Scotch brite 7447 General Purpose Hand Pads Dry the surface with paper towels to remove the dissolved blush before it dries on the surface Sand any remaining glossy areas with 80 grit sandpaper Wet sanding will also remove the amine blush If a release fabric is applied Using WEST SYSTEM Epoxy 70 over the surface of fresh epoxy all amine blush will be removed when the release fabric is peeled from the cured epoxy and no additional sanding is required Epoxy surfaces that have not fully cured may be bonded to or coated with epoxy without wash ing or sanding Before applying coatings other than epoxy paints bottom paints varnishes gelcoats etc allow epoxy surfaces to cure fully then wash and sand Hardwoods Sand with 80 grit paper Teak oily woods Wipe with acetone 15 minutes before coating The solvent dries the oi
92. fasteners 54 removing epoxy 68 repair patch 25 resin 62 rot panel core 31 stringer core 11 roving woven 1 rudder bearings 59 S safety 61 screw fasteners 51 secondary bonding 4 shelf life 79 skin delamination 28 repair 21 skin fiberglass 21 sole cockpit cabin 42 standard techniques 61 78 stiffness improving 10 stringer adding 18 repair 10 replacing 13 surface preparation for epoxy 69 for finish coating 77 T tabbing 10 43 teak deck installing 44 templating foils 57 terminology 3 through bolted fasteners 49 transom core replacement 34 skin remove replacement 33 U unidirectional fiber using 20 V vacuum bagging 26 veneers teak 44 W wet method applying fabric 76 woven roving 2 86 Additional building and repair information available from West System Inc Publications 002 950 WEST SYSTEM User Manual amp Product Guide The primary guide to safety handling and the basic techniques of epoxy use Includes a complete description of WEST SYSTEM epoxy resin hardeners fillers additives reinforc ing materials tools supplies and publications 002 The Gougeon Brothers on Boat Construction 5th Edition This book is a must for anyone building a boat or working with wood and WEST SYSTEM epoxy Includes extensive chapters on composite construction techniques materials lofting safety and tools with many illustrations diagrams and photographs 002 970 Wo
93. ff ee hg sy j gt i om ys o O M ra p di ff f i i _ a y a gt j a P F i ts i l j i m j a r ill n Z i ain F S a the hole to support the new core Provide atemporary backing to support the core while bonding it in position and while laminat ing the new outer skin patch Cut a piece of low density insulating foam slightly larger than the hole opening Bevel the edges of the foam so the face of the foam is flush with the inner skin core bond line Cover the foam with 4 6 mil plastic and brace it in position against the in ner edge of the hole If the foam is too stiff to conform to a curved panel shape when braced from the back sand the foam to a shape that matches the panel curve Figure 5 14 Prepare a new piece of core material to match the shape thickness and density of the core that was removed Dry fit the core to match the shape and contour of the core that was removed When replacing damaged core material try to purchase the same material used by the builder If this is impossible locate a material that is as close as possible to the core s original thickness and density Bond the core material into position Wet out the edges of the hole and the core material with epoxy Apply a layer of epoxy 406 filler thickened to the consistency of peanut butter to the in side edges of the hole and the core material Place the core material in position If the epoxy mixture will not hold the core in place or if it wil
94. fillet size Heavy duty sealable food storage bags with one corner cut off may also be used 73 Using WEST SYSTEM Epoxy 3 Clean up the remaining excess material outside of the margin by using a sharpened mixing stick or a putty knife Figure 9 13 Fiberglass cloth or tape may be applied over the fillet area before the fillet has cured or after the fillet is cured and sanded Sand smooth with 80 grit sandpaper after the fillet has fully cured Wipe the surface clean of any dust and apply several coats of resin hardener over the entire fillet area before final finishing 9 4 4 Fairing Fairing refers to the filling and shaping of low areas so they blend with the surrounding surfaces and appear fair to the eye and touch After major structural assembly has been completed fi nal fairing can be easily accomplished with WEST SYSTEM epoxy and low density fillers Prepare the surface as you would for bonding Section 9 4 1 Sand smooth any bumps or ridges on the surface and remove all dust from the area to be faired Wet out porous surfaces with unthickened epoxy Figure 9 14 Figure 9 14 Wet out porous surfaces before apply Figure 9 15 Trowel the thickened epoxy fairing ing thickened fairing compound compound into the voids and depressions with a plastic spreader Mix resin hardener and 407 Low Density or 410 Microlight filler to a peanut butter consis tency Trowel on the thickened epoxy mixture
95. flush with the inner surface for easy fairing and finishing when the repair is complete 1 Cuta piece of Styrofoam or similar material slightly larger than the hole you will be patching Shape the foam as necessary to match the contour of the repair area if the panel is curved more than the foam can bend The foam should make contact at the edges of the hole Figure 4 2 A temporary backing support should fit tight against the in side of the panel and match the panel con tour Plastic Stiff foam backing Brace 2 Cover the backing support with a piece of plastic and brace it against the hole from the inside The plastic will help seal the hole and prevent the patch from bonding to the foam backing Looking at the hole from the outside the foam should be in contact with the edges of the open ing and the plastic should be smooth and tight Cover the plastic with a piece of release fabric before placing the support over the hole if you prefer to leave the inner surface of the patch textured and ready for finishing 3 With the backing support in position laminate the repair patch as described in Section 4 3 When the repair patch has cured remove the brace and foam Peel the plastic and release fabric from the repair area Fair and finish the interior side of the panel as desired 4 2 2 Backing supports without access If you don t have access to the inside of the panel the following method is designed to provide suppor
96. gan USA All Rights reserved No part of the contents of this book may be reproduced or transmitted in any form or by any means without the written permission of the publisher Printed in the USA WEST SYSTEMA BRAND Table of contents 1 Introduction E 1 1 Typicalfiberglass TRE N 1 2 WEST SYSTEM epoxy for fiberglass repair 2 Repairing Minor Cracks and Holes 2 1 Minor crack and abrasion repair 2 2 Finishing 3 Repairing Stringers and Floors 3 1 Repairing local core damage 3 2 Stringer repair guidelines 3 3 Replacing active core sections 3 4 Replacing stringers 3 5 Reinforcing to improve panclstinces 4 Repairing Damaged Skins 4 1 Assessing and preparing the damaged area 4 2 Backing a repair patch 4 3 Laminating a repair patch 5 Repairing Core Related Damage 5 1 Repairing skin delamination 5 2 Replacing damaged cores 5 3 Repairing transom delamination 5 4 Repairing holed panels 6 Repairing and Upgrading Soles and Decks 6 1 Repairing delaminated soles and decks 6 2 Installing a teak deck 7 Installing Hardware 7 1 Bonding fasteners 7 2 Bonding fasteners and Radare 7 3 Casting epoxy bases for hardware 7 4 Making fasteners removable 7 5 Removing bonded hardware 8 Repairing Keels and Rudders 8 1 Repairing internal ballast keels 8 2 Repairing external ballast keels 8 3 Templating keels and rudders 8 4 Repairing worn rudder bearings 9 Using WEST SYSTEM Epoxy 9 1 Epoxy safety 9 2 Epoxy
97. gent and pre vent the shaft from bonding to the new bearing surface Replace the rudder in the boat and sight the rudder to make sure that it is vertical The keel will serve as a good reference point Brace the rudder to prevent movement 4 Prepare a bearing mixture of epoxy and a blend of 50 406 Colloidal Silica and 50 423 Graphite Powder The epoxy 406 423 mixture should have the consistency of mayonnaise to prevent running or sagging Load the mixture into a syringe 5 Inject enough of the material through each of the three drilled ports to create a 3 4 1 diameter pad between the shaft and the housing at each port Be careful not to move the rudder shaft until the mixture cures thoroughly 6 Break the shaft free by grasping the rudder blade and twisting it If the cured bearing pads are too tight after rotating the rudder briefly which is not typical remove the rudder and apply a buffing compound to the rudder shaft Reinstall the rudder and work it back and forth until it turns freely in the new bearings Lower the rudder once more and thoroughly clean any remaining mold release or buffing com pound from the shaft and bearing surfaces Spread a thin layer of waterproof grease on the shaft and reinstall the rudder This technique is useful for restoring a variety of bearing surfaces The epoxy 406 423 Graphite mixture provides a hard low friction bearing surface The durability of the bearing depends a great deal on the smoo
98. ger supporting them In many boats this will not be a problem but there are some hulls that will be very floppy when the sole is out If the new sole is installed while the hull is out of shape the hull will stay that way 43 Repairing and Upgrading Soles and Decks Figure 6 1 Cut through the fiberglass at the sole hull joint if the ply wood is tabbed to the hull with fiberglass tape or if the sole is covered with a layer of glass CAUTION Do not cut into the hull laminate Support hull with blocking to hold hull shape 3 Cut through the fiberglass at the sole hull joint if the plywood is tabbed to the hull with fiber glass tape or if the sole is covered with a layer of glass Figure 6 1 Remember that this is not a 90 joint the hull is angling toward the centerline Make sure you are not going to cut into the hull laminate as you are cutting the tab Remove all of the fasteners The sole may be screwed to butt blocks between plywood sections cleats attached to the hull at the perimeter and stringers near the center of the sole Pontoon decks will be screwed or bolted around the perimeter Remove the pieces of plywood If you remove them carefully you can use them as patterns for the new sole If only a portion of the sole is damaged you can cut out a section of the sole If there is no structural member below it to make a good place for a joint use cleats bonded under the edge of the remaining original deck
99. ght times stiffer By laminating a lightweight core between two fiber resin skins a lot of stiffness can be gained witha minimum amount of added weight The skins still take all of the tensile and compressive loads caused by bending the panel but the I beam effect produced by the addition of the core allows the panel to withstand much greater bending loads End grained balsa is the most widely used core material in production boats It offers low cost and good impact resistance and compres sive strength to resist the collapsing of skins under load PVC foam cores are available in a vari ety of characteristics They are more expensive than balsa but more resistant to moisture damage Honeycomb core is an open corrugated pattern of paper or other thin material on edge Honeycomb is often used in prefabricated panels for bulkheads and other interior com ponents 1 1 4 Construction methods Generally production fiberglass boat hulls are built in a female mold A release agent is first ap plied to the surface of the mold over which the gelcoat material is applied Gelcoat is usually a pigmented unsaturated polyester resin and may be anywhere from 12 to 22 mils thick It is de signed to act as a moisture barrier for the underlying laminate as well as to provide a smooth glossy cosmetic finish Subsequent layers of fabric are saturated with resin and laid up over the gelcoat There are as many lay up schedules as there are boats A typical hu
100. gure 9 9 Thickened epoxy can be applied immediately over the wet out surface or any time before the wet out becomes completely tack free For most small bonding operations add the filler to the resin hardener mixture remaining in the batch that was used for the wet out Mix enough resin hardener for both steps Add the filler quickly after the surface is wet out and allow for a shorter working life of the mixture Clamp components Attach clamps as necessary to hold the components in place Use just enough clamping pressure to squeeze a small amount of the epoxy mixture from the joint indi cating that the epoxy is making good contact with both mating surfaces Figure 9 10 Avoid us ing too much clamping pressure which can squeeze all of the epoxy mixture out of the joint y p 4 g Figure 9 11 Remove excess epoxy before it begins out of the joint with just the right amount of thick to gel A sharpened mixing stick makes an excellent ened mixture and clamping pressure cleanup tool Remove or shape excess adhesive that squeezes out of the joint as soon as the joint is secured with clamps A wooden mixing stick with one end sanded to a chisel edge is an ideal tool for re moving the excess Figure 9 11 Single step bonding Single step bonding is applying the thickened epoxy directly to the component without first wetting out with resin hardener only We recommend that you thicken the epoxy no more than i
101. h 1 part hardener To measure 105 Resin and 207 or 209 Hardener by volume combine 3 parts resin with 1 part hardener by weight 3 5 parts resin to 1 part hardener First time users If this is the first time you have used WEST SYSTEM epoxy begin witha small test batch to get the feel for the mixing and curing process before applying the mixture to your project This will demonstrate the hardener s open time for the temperature you are working in and assure you that the resin hardener ratio is metered properly Mix small batches until you are confident of the mixture s handling characteristics Mixing Stir the two ingredients together thoroughly at least one minute longer in cooler tempera tures Figure 9 5 To assure thorough mixing scrape the sides and bottom of the pot as you mix Use the flat end of the mixing stick to reach the inside corner of the pot If you are using a power mixer occasionally scrape the sides and corners of the mixing pot while mixing If you are going to be using the mixture for coating quickly pour it into a roller pan to extend the open time WARNING Curing epoxy generates heat Do not fill or cast layers of epoxy thicker than Y thinner if enclosed by foam or other insulated material Several inches of mixed epoxy ina plastic mixing cup will generate enough heat to melt the cup if left to stand for its full pot life For this reason do not use foam or glass mixing containers If a pot of mixed epoxy begin
102. h ep oxy just prior to installing screws for motor mounts and transom hardware Apply mold release or vegetable oil cooking spray to the fasteners prior to gluing them in place if you plan to re move them at some point in the future Replacing the core and both skins If you can t separate the skins from the core or if the skins and core are damaged beyond repair cut the entire transom section out and bond in a new core as follows Cut away the transom by sawing through the skins and core at the perimeter of the transom Prepare the bonding area by sanding away any rough or uneven edges around the hole perime ter Be sure the hull is supported to prevent distortion Prepare the transom core replacement as described above 5 3 3 Bond the plywood pieces to gether on a flat surface or a surface matching the curve of the transom Trim the perimeter of the new core checking the piece for fit in the exact position of the old core Be sure the hull is set up square and true before bonding the new transom in place Bond the new core in position Wet out the bonding surfaces of the new plywood core and the hull with epoxy Use particular care to thoroughly wet out the end grain of the plywood Coat the bonding surfaces of the core and hull with an epoxy 404 filler mixture thickened to the consistency of mayonnaise Use enough of the mixture to ensure no voids remain between the two surfaces when the core is positioned Clamp or
103. he gelcoat suppliers Frequently local repair yards that do fiberglass repairs will sell these products There are gelcoat additives available through most gelcoat suppliers that when used properly make matching a repair easier These are clear low viscosity resins that are not air inhibited These products are mixed with the pigmented gelcoat in place of a wax solution to provide a tack free cured surface They also provide the added benefit of thinning the gelcoat without changing the color of the cured patch the way acetone or styrene can Gelcoat additives are manufactured by Duratec and Cook Paint and Varnish Company Matching the repair color to the color of the boat can be difficult Most gelcoat colors change as they cure As you tint the gelcoat to match apply a small amount of uncatalyzed material to the sanded area surrounding the repair Use your gloved finger to spread this into a sample the size of a quarter Wait a couple of minutes for the solvents to flash off Any color variation will be ev ident If the color match is not acceptable change the color by adding small amounts of tinting pigments As you adjust the gelcoat color think in terms of the basic color hues 1 e the color needs to be more red blue green or yellow This will help you identify which of the pigments to use Use very small amounts of the pigments When the hue is right adjust the brightness darker or lighter by adding black or white It will take much
104. he to laminate a backer that matches the panel contour panel to permanently bond the backer in position 3 Wet out the layers of fabric with epoxy Pour a small amount of resin hardener mixture in the middle of the cloth Use a plastic spreader to spread the mixture over the cloth until both layers are completely saturated Place the wet out fabric against the waxed panel Figure 4 3 Use a spreader to smooth the cloth against the panel and remove excess epoxy The paste wax will prevent the cloth from be coming bonded to the panel If the hole is in a flat or moderately curved area of the panel the backer can be laminated on the flat table The cured backer should be flexible enough to con form to a moderately curved panel Allow the backer to cure thoroughly Peel the cured backer laminate from the panel or table Using a utility knife or scissors trim the laminated backer to the shape of the hole 1 larger than the hole on all sides To help handle and hold the backer in position when bonding screw two or more sheet metal screws into the laminate and attach a length of heavy string or wire to each screw The string will also help re trieve the laminate if you accidentally drop it behind the panel Bonding the backer in place 1 Prepare the inside of the opening for bonding Reach through the opening and sand the inside edge of the hole thoroughly with 50 grit sandpaper Bend the laminate slightly so that you can pass it thr
105. he inner skin and make repairs as neces sary Sand rough surfaces Remove all loose material and dust 2 Wet out the bonding surfaces of the inner fiberglass skin and first piece of core with epoxy Ap ply extra epoxy to the plywood end grain 3 Coat the bonding surfaces of the inner skin and hull edges with an epoxy 403 or 406 filler mix ture thickened to the consistency of mayonnaise Use a notched spreader to apply enough thick ened epoxy to bridge all gaps between the core piece and the skin and the edge of the core and the hull Avoid over thickening The epoxy needs to move under minimum pressure Adjust vis cosity by adding more or less filler to achieve consistency between that of catsup and mayonnaise 4 Place the first piece of plywood in position against the coated skin Figure 5 10 Clamp the piece in place with drywall screws and oversized washers through the inner skin to draw the pieces of core tight to the inner skin Coat the screws with a mold release for easy removal A small amount of epoxy should squeeze from the joint around the core Fill the screw holes with epoxy after the lay up has cured 5 Repeat the process for the remaining pieces of the first layer Fill any gaps and smooth the ep oxy at the joints Remove excess epoxy before it begins to gel Allow the epoxy to cure thor oughly before removing screws clamps or vacuum pressure Once cured you have a rigid base against which you can glue or laminate the
106. he techniques described in this manual are based on the handling characteristics and physical properties of WEST SYSTEM Epoxy products Because physical properties of resin systems and epoxy brands vary using the techniques in this publication with coatings or adhesives other than WEST SYSTEM is not recommended This manual is updated as products and techniques change If the last copyright date below is more than several years old contact your WEST SYSTEM dealer or West System Inc Refer to the current WEST SYSTEM User Manual amp Product Guide for complete product information and safety and handling information The information presented herein is believed to be reliable as of publication date but we cannot guarantee its accuracy in light of possible new discoveries Because West System Inc cannot control the use of its products in customer possession we do not make any warranty of mer chantability or any warranty of fitness for a particular use or purpose In no event shall West System Inc be liable for incidental or consequential damages WEST SYSTEM and Scarffer are registered trademarks and Microlight and Episize are trade marks of West System Inc Bay City Michigan USA Copyright February 1987 August 1987 January 1988 September 1988 May 1992 April 1993 May 1994 January 1996 August 1998 June 2000 June 2001 February 2003 June 2004 December 2006 by West System Inc Published by West System Inc Bay City Michi
107. idely They can also be made on a diagonal to stagger them even more Joints near the sides of the transom will affect strength less than joints near the middle Remem ber the cantilevered load of an outboard motor puts significant loads on the middle of the tran som If joints in the layers are scarfed with an 8 1 bevel rather than butted joint location is not an issue Before mixing epoxy e Plan all of the installation steps The layers can be glued in place in one continuous operation or over several sessions e Label the pieces and dry fit them in the transom to eliminate potential problems during actual assembly The fit need not be perfect thickened epoxy will bridge gaps e Use 206 Slow Hardener for extra working time Use 209 Extra Slow Hardener if you will be working in warm temperatures e Be sure you and any parts of the boat you do not want to get epoxy on are protected e Besure all parts tools and clamps are within easy reach Drywall screws are a practical clamp ing method for a plywood transom lay up Clamps wedges or prop sticks can also be used Bolts with nuts and oversized washers can be used in places where holes will eventually be re quired motor mount holes and drain holes 5 3 4 Installing the new core If you will be working alone and wish to accomplish the repair in manageable steps laminate the new pieces of plywood core in place as follows 1 Prepare all bonding surfaces Check the condition of t
108. ides of hardware item and backing plate Excess epoxy Uo Ea Backer plate 51 Installing Hardware 10 tener holes and guide the bolts through the slits in the tape The tight fit of the tape around the bolts should keep most of the epoxy from squeezing out of the holes Remove the tape after the bolts are in position Place the backing plate over the bolts in position against the inner side of the panel Tighten the nuts until epoxy begins to squeeze from the sides of the hardware item and backing plate Figure 7 4 Do not over tighten the fasteners Clean away any squeezed out epoxy mixture with a chisel shaped mixing stick and remove the masking before the epoxy begins to gel Allow the epoxy to cure at least 24 hours before applying load to the hardware Allow more time in cool weather Tighten the nuts completely after the epoxy cures thoroughly You may wish to upgrade a hardware attachment that was screwed into the laminate or through bolted with washers instead of a backing plate Often adequate backing plates were not installed by the original manufacturer causing hardware items to over stress a localized area You can increase the load carrying ability of the hardware and reduce stress concentra tions by fabricating a plywood or metal backer and installing it as described above 7 2 2 Screw type fasteners If hardware is screwed to a cored or non cored panel without additional blocking the fasteners rely primari
109. ides of the crack provides more bonding area for the repair It may be more Repairing Minor Cracks and Holes 6 Wi Figure 2 2 Open shallow and minor cracks with a Figure 2 3 Grind out an area of many closely spaced or deep V shaped scraper such as a sharpened can opener cracks with a disk grinder effective to grind out an entire area of many closely spaced or deep cracks Figure 2 3 Scrape or grind as deep as necessary to reach solid undamaged material The depth of the crack will de termine which course of repair to follow a Shallow cracks or scrapes that affect only the gelcoat layer may be repaired with the gelcoat repair technique described in Section 2 2 1 If necessary reinforce the laminate to reduce flex ing as described in Section 2 3 Some small cracks or chips can be filled with a gelcoat touch up kit b Minor cracks or scrapes that run through the gelcoat into the first chopped strand mat layers of the laminate Figure 1 1 should be repaired with epoxy using the procedures described be low Section 2 1 Finish with the gelcoat repair technique described later in Section 2 2 1 If necessary reinforce the laminate to reduce flexing as described in Section 3 c Deep cracks extending into woven fabric of the laminate require a structural repair before be ginning the cosmetic gelcoat repair If the crack extends into or through the woven fabric of the skin follow the procedures in Section 4 If a core has dela
110. in and hardener thoroughly the resin flows through the dispensing pumps and out of containers with greater difficulty the cold epoxy and hardener are prone to clinging to the surfaces of the pumps containers and mixing tools and they resist be ing completely blended unless mixed very thoroughly Remember because of the low tempera ture the chemical reaction isn t going off as well either Compounding a less efficient exothermic reaction with potential for incomplete and or inaccurate mixing you have the recipe for a permanently deficient bond Second the mixed epoxy is much harder to apply If you ve ever tried to spoon honey right out of the refrigerator instead of at room temperature you know just what we re referring to the chilled mixture has become stiff When cold temperatures make epoxy stiff it s extremely diffi cult to coat and wet out surfaces Third air bubbles may be introduced when mixing and held in suspension due to the chilled ep oxy s increased surface tension This can be especially troublesome in clear finish applications Cold weather techniques Up to this point we ve told you all of the reasons why cold weather epoxy usage is difficult and potentially dangerous However with a little advance planning and certain simple precautions all of these problems can be addressed and their consequences avoided The following are six basic cold weather rules We ve used these guidelines for over 20 years and h
111. ining strips in place several at a time following the same procedure Adjust the number of strips or size of the batch of epoxy as necessary Allow the epoxy to cure thoroughly before removing clamps 8 Remove the screws and washers within 24 hours Tighten the screw slightly 5 before backing it out If you have difficulty removing a screw heat the head with a soldering gun s cutter tip While the screw is still hot try to unscrew it again Repeat until you are successful 9 Fill the screw holes with epoxy 404 423 Graphite mixture A syringe loaded with the mixture will speed the process If the screws penetrated a panel seal the back of the hole with duct tape before filling the hole 10 Sand to level the surface and remove saw marks from the teak surface Use a belt sander or disc sander with 50 grit sandpaper for the initial sanding A commercial floor sander works well for large decks Finish with 80 grit then 120 grit sandpaper The teak surface may be left natural or finished with a marine grade teak oil marine varnish or WEST SYSTEM 105 Resin 207 Hard ener and a high quality two part polyurethane varnish 6 2 2 Installing teak planks An alternative method allows the use of teak strips up to 3 4 19 mm thick The top surface of a thick plank will expand and contract much more than the bottom bonded surface of the plank because the moisture content varies more at the top surface Because of this expansion differen tia
112. iring Keels and Rudders The thin foil shape that allows many keels and rudders to perform efficiently under water also makes them vulnerable to damage especially from grounding This section provides proce dures to repair common problems of keels and rudders Modern self righting sailboats have either internal or external ballast keels An external ballast keel is a foil shaped iron or lead casting bolted to the outside of the hull The keel bolts pass through the skin into the hull structure An internal ballast keel involves placing the lead casting into a molded fiberglass hull cavity The keel s outer foil shape is an extension of the hull s fiber glass skin surrounding a cast lead core 8 1 Repairing internal ballast keels Internally mounted ballast offers some structural advantages over external ballast but presents some potential problems When a boat with internal ballast is heavily grounded the fiberglass skin takes the brunt of the collision Unlike lead the fiberglass laminate is not malleable so re pairs can become more complicated Further due to the difficulty builders encounter in trying to mate the cast lead ballast with the inside of the laminated keel pocket irregularities and voids often occur between the lead and the fiberglass laminate If moisture finds its way into these voids additional delamination can occur particularly in areas where freezing temperatures can cause expanding ice to further wedge the skin fr
113. is smaller than about 1 diameter c the hole through the outer skin of a cored panel reveals undamaged core material Provide backing to support the lay up of the repair patch as described in Section 4 2 if a the hole through a non cored panel is larger than about 1 in diameter b the hole through the inner skin of a cored panel is larger than about 1 in diameter 4 2 Backing a repair patch If the hole through the skin is larger than about 1 a backing will be required to support the wet out fabric patch in the shape of the panel until the patch cures Applying a support to the back of a panel is generally not a problem if you have access to the inside of the damaged panel But if your boat has a fiberglass liner or if the back of the hole is inaccessible an alternative method must be used Several methods for backing are suggested in this manual Use the method or a modification of one that is most appropriate for your situation If you are using vacuum bagging to laminate the patch an air tight backing is necessary for all holes Suggested backing supports for cored panels with and without back access will be discussed in Section 5 The following are suggested backing supports for non cored panels with and without access to the back of the panel 23 Repairing Damaged Skins 4 2 1 Temporary backing support with inside access If the hole is in an exposed interior area the following backing method will leave the repair
114. ith 50 grit paper 10 Sand the cast base to the desired final finish Begin with 50 grit sandpaper or a file if the base is extremely irregular Finish with 80 grit sandpaper 11 Bond the hardware to the cast base using the hardware bonding procedure in Section 7 1 1 Fig ure 7 7c Drill oversized and standard pilot holes for the fasteners through the cast base Allow to cure at least 24 hours before reassembling or applying loads to the hardware Allow more time in cool weather Apply three coats of resin hardener mixture to the base before final finishing 7 4 Making fasteners removable Testing at West System Inc has shown that with bonded fasteners screws bolts threaded rods etc the adhesive bond to the metal is not as important as the keying between the epoxy and the threads of the fastener This factor allows the builder to coat the fastener with a thin film of mold release before bonding to permit easy fastener removal after the epoxy cures Fatigue tests of bonded threaded rods with and without a thin coating of mold release show only a 4 10 reduction in the overall fatigue strength of the fastener with mold release A thin film mold release will yield a more predictable performance than a thick film Mold release may include paste wax nonstick cooking spray silicone spray or hair spray While the reduction in strength of the fastener treated with mold release is slight it should be taken into account when calculating
115. ively small damaged area around the motor mount If the damage is limited it may be easier to repair the damage in the center of the skin after re bonding the skin rather than laminating a new skin over the entire transom Repair the skin using the appropriate procedure in Section 4 after the skin is replaced re bond the original skin as follows Sand the bonding surfaces of the core and the skin If the skin was repaired be sure the back side of the repair is sanded flush Dry fit the skin to be sure it lays flat and fair with the adjoining skin Wet out the bonding surfaces of the core and skin with epoxy Bond the skin to the core in its original position using the same laminating techniques used to bond the plywood core in place Clamp the skin with drywall screws driven through plywood blocks or oversized washers Large blocks or washers spread the holding power of the screws over a larger area and prevent lt Figure 5 10 Grind a mini Wi mum 12 to 1 bevel on both sides of the joint Laminate a repair patch over the joint to restore skin continuity 12 to 1 bevel New laminated plywood core Repairing Core Related Damage 38 dimples in the fiberglass skin that would require filling and fairing later Use pieces of plastic sheet under the washers or blocks to prevent bonding to the skin Allow the epoxy to cure Re move the screws and fill the holes with epoxy 4 Grind a minimum 12 to 1 bevel on both sides of the join
116. ized bit or enlarge holes with a round file to increase bonding area Drill through the outer skin and core only Remove about 2 12mm of core material around the hole witha bent nail or an Allen wrench chucked into a drill motor Figure 7 2 The spinning nail or Allen wrench will pulverize the core material without damaging the skins provided you are careful Seal the underside of the holes with duct tape and fill the holes completely with an epoxy 406 or 404 filler thickened to the consistency of mayonnaise Allow the mixture to cure thoroughly Installing Hardware 50 4 Figure 7 2 Remove about 1 2 12mm of core material Figure 7 3 Re drill slightly oversized fastener holes through around the hole with a bent nail or an Allen wrench chucked the cured epoxy into a drill motor 4 Temporarily place the hardware item in position and trace the outline of the base and the fas tener holes with a pencil Re drill slightly oversized fastener holes through the cured epoxy Figure 7 3 5 Mask off the outside of the marked area and cover the area beyond the tape with plastic sheeting for protection from spills 6 Thoroughly sand the surface within the masked area with coarse sandpaper to provide good mechanical keying for bonding Sand the contact surface of the hardware item with coarse sandpaper to expose fresh metal Mask off the area not to be bonded on the hardware item to prevent contamination Re tape the underside of the fas
117. kin Figure 5 5 The skin should separate easily in areas where the core is dam aged or wet In areas where the skin is well bonded to the core use a chisel or thin blade between the skin and core to pry the skin away from the core material Be careful not to bend the skin too much or gouge the core Applying heat to the joint with a heat gun will also help to soften the skin core bond Be careful not to overheat the skin 3 Dry the core thoroughly If the core is extremely wet start by using a high powered shop vac uum cleaner or vacuum bagging to draw water out of the laminate A heat lamp or heat gun will speed the drying If the core is undamaged skip the core replacement and re bond the skin as described in Section 5 2 1 Repairing Core Related Damage 32 Figure 5 5 Cut through the skin only outside of the area of Figure 5 6 Fit a new piece of core material to match the delamination Pry the skin carefully away from the core mate shape thickness and density of the damaged core material that rial 4 5 was removed Remove damaged core material Cut around the area of damage with a utility knife Use a chisel to remove the damaged core and shave all traces of core from the opposite skin Prepare a new piece of core material to match the shape thickness and density of the core that was removed Dry fit the piece to be sure the new piece is no higher than the surrounding core Figure 5 6 When replacing damaged core materi
118. l Remove with water See 9 4 1 Special preparation for various materials Cured epoxy Red color will not affect epoxy performance Avoid using for coating or exposed areas where color is not desired PROBLEM Runs or sags in coating Fairing compound epoxy 407 or 410 mixture sags and is difficult to sand Paint or varnish will not set up over epoxy Epoxy became very hot and cured too quickly Bubbles formed in coating over porous surface bare wood or foam Pinholes appear in epoxy coating over abraded fiber glass or epoxy Fish eyeing in coating POSSIBLE CAUSES Epoxy applied too thick Coating curing too slowly Fairing material not thick enough Epoxy not completely cured Paint incompatible with epoxy Epoxy surface not thoroughly prepared Batch too large Temperature too warm for the hardener Application too thick Air trapped in pores escapes through coating outgassing as the materials temperature is ris ing Surface tension causes epoxy film to pull away from pinhole before it gels Contamination of the coating or surface or improper abrasion or the undercoating 84 PREVENTION 1 Use 800 Roller Covers and roll the coating out into a thinner film A thin film will flow out much smoother than a thicker film after it is tipped off with the foam roller brush 2 Warm the epoxy to thin it or apply the coating ata warmer temperature See 9 4 6 Barrier coating 1 Apply the co
119. l a more yielding material such as flexible caulk is more appropriate for the upper portion of these joints This method uses epoxy to bond planks to the substrate but uses a flexible caulk to fill the gap between planks The steps for preparing and placing teak planks is the same as for installing veneers Instead of filling the gap between strips with epoxy as the planks are clamped down clean excess epoxy out of the gap Epoxy should fill no more than 1 3 of the height of the plank Figure 6 5 right After the epoxy cures remove the clamping screws and fill the fastener holes with epoxy as with the veneer method Prepare the sides of the teak planks for bonding they should be clean dry 47 Repairing and Upgrading Soles and Decks and sanded Mask off the gaps to make caulking neater Fill the remaining gap between planks with a flexible caulk such as polysulfide Sand the deck smooth after the caulk has cured E 47 Installing Hardware 7 Installing Hardware Hardware attachment is a critical and often overlooked element in a boat s structure Over time high loads and fatigue can cause hardware fasteners to loosen not only reducing the load carrying ability of the hardware but creating a source for leaks into the laminate Leaks at hard ware locations are the most common cause of skin delamination and core damage Often the first indication of loose hardware is an area of delaminated deck nearby This section provides procedure
120. l checking for a soft feel and or skin movement Tap around the suspected area lightly with a small hard object to help reveal the area of delamination A void under the skin will sound flat or dull compared to a more resonant sound of a solid laminate When you push against the surface the delaminated skin will give easily until it hits the core If the core is solid the skin will appear fair when it s pressed tight against the core If the core is damaged or deteriorated you will be able to push the skin below the fair surface of the deck or hull Water or air may squeeze from a nearby crack or hardware fastener Determine the condition of the core material by drilling 6 42 Smm diameter inspection holes through the skin several inches apart over the delamination Push the skin tight against the core and drill through the core without drilling into the opposite skin Collect the core material removed by the drill Squeeze the core material tightly between your thumb and finger to deter mine whether the material is wet or dry and examine it for signs of decay You may also insert a wire or nail through the hole to probe the core If you hit voids or the core feels soft or punky the core should be replaced 5 1 2 Re bonding delaminated skin to a dry core If the core material is firm and dry re bond the skin by injecting epoxy between the skin and core as follows Cut 14 28mm from the tip of a WEST SYSTEM 807 syringe Cut
121. l matrix The mixture has become a thermoset plastic solid used in this case to hold bundles of fibers together in the shape of a boat Fibers used in production fiberglass boats take the form of various types of fabrics including mat chopped strand mat woven cloth and roving and uni directional bi axial and tri axial cloth Each fabric type offers different properties and they are often used in combination to provide specific strength or stiffness properties in different parts of a laminate Fabric selection may also be based on handling characteristics and cost Most fabrics are woven or stitched to gether bundles of individual continuous pultruded fibers of various synthetic plastics The least Introduction 2 expensive and most common fiber used in production boats is E glass It is widely available and used extensively for repair Fibers may also be made of more exotic and expensive materials like aramid or graphite These fibers offer much higher strengths as well as higher costs and are used primarily in one off high performance boats where saving weight is worth the higher cost Stitched fabrics represent a major advancement in composite technology by allowing higher fiber to resin ratios and stiffer laminates than woven fabrics of equal weight 1 1 3 Cores Cores are used in laminates to increase stiffness of a panel without adding a proportional in crease in weight Doubling a panel s thickness can result in a panel that is ei
122. l at the surface and allows epoxy to penetrate Be sure the solvent has evaporated before coating Porous woods No special preparation needed If surface is burnished possibly by dull planer blades sand with 80 grit paper to open pores Steel lead Remove contamination sand or grind to bright metal coat with epoxy then sand fresh epoxy into surface Recoat or bond after first coat gels Aluminum Sand and prepare with 860 Aluminum Etch Kit Polyester fiberglass Clean contamination with a silicone and wax remover such as DuPont Prep Sol 3919S Sand with 80 grit paper to a dull finish Plastic Adhesion varies If a plastic is impervious to solvents such as acetone epoxy generally will not bond to it Soft flexible plastics such as polyethylene polypropylene nylon Plexiglas and polycarbonate fall into this category Hard rigid plastics such as PVC ABS and styrene provide better adhesion with good surface preparation and adequate bonding area After sanding flame oxidizing by quickly passing pro pane torch over the surface without melting the plastic can improve bonding in some plastics It s a good idea to conduct an adhesion test on a plastic that you are uncertain about 9 4 2 Bonding gluing This section refers to two types of bonding Two step bonding is the preferred method for most situations because it promotes maximum epoxy penetration into the bonding surface and pre vents resin starved joints Single step bon
123. l damage to either the core material or skins to moisture related core deterioration to collision damage that can leave a hole through both the core and the inner and outer skins The repair procedures in this section begin with the least damage easiest to repair 1 Repairing skin delamination Often the core is wet but still firm and usable A delaminated area may be several square inches or several square feet 2 Replacing damaged cores The skin may be intact but moisture penetration over time may have caused the balsa core to deteriorate An impact may puncture the outer or inner skin and core without affecting the other skin Even a minor puncture can allow moisture to migrate under 5 the skin and affect strength of the core over a large area 3 Repairing transom delamination The plywood core may delaminate or rot as a result of mois ture penetration through a crack or hole in the transom skin 4 Repairing holed panels An impact or modification can require rebuilding of the entire panel structure Impact damage can extend to both skins and core or one skin with major core damage The work required to repair each type of damage varies with the size of the damaged area Of ten the full extent of damage cannot be determined until you have removed a portion of the outer skin as described in Section 4 1 Assessing and preparing the damaged area After a thor ough inspection and assessment of the damage follow the procedure
124. l not conform to the panel contour use braces to hold it in position Smooth any excess epoxy at the joint and fill any voids in the joint before the epoxy begins to gel Allow the epoxy to cure thoroughly Laminate a new outer skin repair patch following the procedure in Section 4 3 Finish the repair following the procedure in Section 2 Fi 41 Repairing Core Related Damage 6 Laminate a new inner skin repair patch following the procedure in Section 4 3 after removing the temporary backing support Finish the repair as desired 5 4 2 Repairing holes through cored panels without back access The difference between repairing holes with or without back access is in the sequence of steps Without back access it s necessary to laminate the inner skin first replace the core and then laminate the outer skin Laminating the inner skin from the outside requires additional preparation as follows 1 Prepare the hole by cutting away ragged or damaged skin Cut back to undamaged core and skin while maintaining a circular or oval hole shape 2 Cut back the outer skin and core several inches from the edge of the hole through the inner skin to provide an area wide enough to grind a 12 to 1 bevel around the edge of the inner skin Fig ure 5 15 Use a router with a straight fluted bit set to the depth of the outer skin and core only to avoid cutting the inner skin Cut the core and outer skin back 12 times the thickness of the in ner ski
125. lace the fiberglass skin as described in 3 5 3 4 1 Applying the fiberglass skin After repairing or replacing core material it is necessary to replace the fiberglass skin and tab the stringer to the hull To duplicate the strength of the original skin it is important to duplicate the thickness of the original skin and to properly prepare the surfaces for a good bond Preparing the fiberglass fabric Measure the thickness of the skin on the original stringer Keep in mind the top skin may be thicker than the sides and the tabbing Refer to the chart in Appendix A to determine the num ber of layers of a particular weight fabric necessary to achieve the thickness required Cut the necessary number of strips of fiberglass fabric the length of the stringer Cut the first piece large enough to extend as far as the original tabbing from each side of the stringer Cut each of the remaining pieces 1 2 each side narrower than the previous one When laying out the layers of fabric do not allow the tabbing edges to end at the same place For stress reduction step the edges of the fabric to create a tapered edge If you fail to do this all the load the stringer is carrying will be transferred to the line on the hull s surface where the tabbing ends and the hull may crack at that point If however you step the tabbing edges the load from the stringer is gradually distributed to the hull Where stringers end at a bulkhead or the transom wrap the glass
126. leave the over lap and fair in the unevenness after coating Figure 9 22 Apply the first coat of un thickened epoxy to fill the weave of the cloth before the wet out coat be comes completely tack free Using WEST SYSTEM Epoxy 76 9 Coat the surface to fill the weave before the wet out becomes completely tack free Figure 9 22 Follow the procedures for epoxy barrier coating under Section 9 4 6 It will take two or three coats to completely fill the weave of the cloth and to allow for a final sanding that will not affect the cloth Wet method An alternative is to apply the fabric or tape to a surface coated with wet epoxy As mentioned this is not the preferred method especially with large pieces of cloth because of the difficulty removing wrinkles or adjusting the position of the cloth as it is being wet out However you may come across situations when this method may be useful or necessary 1 Prepare the surface Section 9 4 1 2 Pre fit and trim the cloth to size Roll the cloth neatly so that it may be conveniently rolled back into position later 3 Roll a heavy coat of epoxy on the surface 4 Unroll the glass cloth over the wet epoxy and position it Surface tension will hold most cloth in position If you are applying the cloth vertically or overhead you may want to wait until the ep oxy becomes tacky Work out wrinkles by lifting the edge of the cloth and smoothing from the center with your gloved hand or
127. ll section might con sist of the layer of gelcoat several alternating layers of mat and woven roving and in many cases a core material such as end grain balsa or foam followed by several more alternating layers of saturated mat and woven roving Figures 1 1 and 1 2 Hull thickness may vary from boat to boat Older boats were often laid up with a solid glass laminate thickness of 11 2 3 8 cm to as much as 5 12 7 cm in the keel areas of the more heavily built boats Today however the trend is toward thinner lighter laminates making the structural integrity of each of the laminate components all the more critical Standard lay up relies on gravity to hold all of the resin saturated material in place until cured The technique of vacuum bag laminating has advanced composite construction by allowing the lt lt __ Gelcoat Gelcoat a go Outer skin Alternating z mat and roving Core material Alternating layers of mat and woven roving Inner skin Alternating mat and roving a a dL ji Figure 1 1 Typical solid single skin fiberglass laminate Figure 1 2 A typical cored laminate consists of end grained Various reinforcing fabrics are bonded together with polyester balsa or other core material sandwiched between two resin fi resin ber skins Introduction builder to compress the entire wet out laminate evenly in the mold and more accurately con trol the resin content
128. ly on the skin for holding power Bonding the fasteners in epoxy can greatly im prove holding power by increasing the load transfer area around the fastener If the hardware is screwed to a cored panel or a non cored panel with blocking prepare the panel and bond the hardware for increased load transfer as follows Remove the loose hardware and thoroughly clean dirt paint sealants etc from the hardware and the deck or hull surface Wipe both surfaces with solvent to remove any residue or contami nants If the panel is cored inspect for delamination or core damage and make the necessary core repairs before reattaching hardware see Section 5 Drill an oversized hole around each existing fastener hole to increase the amount of skin and core area that the epoxy around the fastener can bond to This may be much larger than the fas tener twice the fastener diameter for example If the fastener still has holding power at the bottom of the hole drill the oversized hole 2 3 to 3 4 the depth of the fastener This will leave material for the bottom threads of the fastener to bite into and provide some clamping pressure when the hardware is bonded in position Figure 7 5 left In some cases if the hardware is being mounted to a horizontal surface for example gravity or weight can provide enough clamping pressure to hold the hardware and the fasteners in posi tion In this case drill the oversized hole to the full length of the fastener
129. methods 2 controlling cure time 66 cores in construction 2 panel damage 28 replacing stringer 12 stringer damage 11 coverage coating 79 cracking 5 cure stages 64 D deck repair 42 teak installation 44 delamination skin core 28 sole and deck 42 transom 33 dispensing epoxy 66 disposal epoxy 62 dry method applying fabric 74 E estimating guides 79 epoxy product description 62 F fairing filler description 64 technique 73 fastener bonding 47 fiberglass applying over stringers 14 in construction 1 reinforcing with 16 skin repair 21 fillers proportions 79 description 63 fillets 72 final cure phase 65 finishing 7 floors 10 foam cores 19 G gelcoat blisters 3 gelcoat finish 7 graphite bearing 60 H half round cores 19 hardeners 62 hardware bonding 47 installing 47 hazards 61 holed panels 39 hydrolysis 3 inactive core 11 initial cure phase 64 K keels external ballast 56 internal ballast 55 templating 57 a laminated stringers 18 lead keel 56 M mat chopped strand 1 mini pumps using 66 mixing epoxy 67 O open time 64 P paint finish 9 planks teak 46 plastic bonding to 70 plywood sole deck repair 42 transom core 33 polyester 1 polyurethane paint 9 Index preparation for bonding 69 problem solving 83 R recoating 77 reinforcing 16 reinforcing flexible panels 16 removable fasteners 54 removing bonded
130. mid conditions Provides approximately twice the pot life and working time as 206 Slow Hardener and adequate pot life up to 110 F 43 C Also used at room temperatures when a long pot life and working time are required 3 1 mix ratio Hardener Selection Guide Figure 9 1 Select a hardener for its intended use and for the HARDENER TEMPERATURE RANGE F CURE SPEEDS at room temperature cure speed best suited for your job in the tempera ture range you are work ing in 9 2 2 Fillers saiad RESIN HARDENER USE l l POT LIFE OPEN TIME SOLID 40 50 60 70 80 90 100 thin film eos Scars O ee Seles 20s e E ESSE 207 Ces cozina A e aon aeg __ ERI Epoxy cures faster in warmer temperatures and in thicker applications Epoxy cures slower in cooler temperatures and in thinner applications Throughout this manual we will refer to epoxy or resin hardener mixture meaning mixed resin and hardener without fillers added and thickened mixture or thickened epoxy meaning resin hardener with one of six fillers added Fillers are used to thicken the epoxy for specific applications They are categorized as either Ad hesive Fillers used for structural bonding or gluing and gap filling or Fairing Fillers used for cosmetic surface filling Although each filler has unique handling and cured characteristics that make it more suitable for some jobs than others Figure 3 2 for most bonding applications any of the
131. minated or is damaged from moisture penetration or impact follow the appropriate procedure in Section 5 2 1 Minor crack and abrasion repair Minor cracks and scrapes that extend to the chopped strand mat layers of laminate may be re paired with WEST SYSTEM epoxy Scraped out damage If cracks were exposed with a V shaped scraper complete the repair as follows after prepar ing the damaged area as described above 1 Feather the edges with the scraper or with 100 grit sandpaper and brush the surface free of dust and loose material 2 Wet out the cracks with a resin hardener mixture 3 Fill the cracks with a thickened epoxy mixture using the flat end of a mixing stick or a plastic spreader Thicken the resin hardener mixture to the consistency of peanut butter with 404 or 406 filler Trowel the mixture flush with the surface and remove excess epoxy before it begins to cure Allow the epoxy to cure thoroughly 4 Sand the area smooth Use 100 grit paper to remove any bumps or ridges Finish by wet sanding with 220 grit 5 Finish the area with gelcoat or paint following the procedure in Section 2 2 Reinforce the lami nate as necessary to reduce flexing following the procedure in Section 3 7 Repairing Minor Cracks and Holes Ground out damage If the damage is the result of a scrape or gouge or cracks were exposed with a grinder complete the repair as follows 1 Grind a shallow bevel around the damaged area Remov
132. mixture to bed the plywood into For partial replacement of the plywood or multiple sheets of plywood dish out the joint between plywood pieces with a grinder and join the pieces together with fiber glass tape to make a continuous panel Or in the case of a pontoon deck install the new deck by screwing the plywood down to the stringers Coat the fastener holes with epoxy before inserting the screws This will prevent moisture from getting into the plywood end grain at the fastener holes We usually coat or fiber glass the top side after the sole is installed 6 1 3 Tabbing the sole to the hull 1 Prepare the hull surface for bonding by sanding a 4 6 10cm 15cm wide strip on the hull above the sole with 80 grit paper Repairing and Upgrading Soles and Decks 44 2 Mix WEST SYSTEM epoxy and add either 406 Colloidal Silica or 407 Low Density filler to create a mixture with a peanut butter consistency 3 Apply a fillet of thickened epoxy all along the hull to sole joint This will fill any gap between the plywood and the hull and allow the fiberglass tabbing to lay easily across the joint 4 Apply 4 wide 727 Biaxial fiberglass tape over the fillet Figure 6 2 Wet out the tape with ep oxy If necessary apply multiple layers of tape to build up to the same thickness as the original tabbing Stagger the edges of the tabbing when using multiple layers so they do not end in the same place on the hull side or sole Apply the first lay
133. more white pigment to lighten a mixture than it will a small amount of black pigment to darken it Apply an uncatalyzed smear with each change of color no matter how small Leave each of these smears on the surface until you have the color as close to the boat color as you can get it When you are satisfied with the color match wipe away all of the test smears with acetone or lacquer thinner Divide the batch into a 2 3 portion and a 1 3 portion Our technique for using the patching ad ditives is slightly different than the recommended procedure Mix the patching additive with equal parts of the 2 3 portion of the matched gelcoat Catalyze following the recommendations of the gelcoat supplier Over or under catalyzation may pre vent the product from reaching a proper cure Apply this mixed gelcoat to the repair with a spray gun Apply several light coats feathering each one farther from the repair area Allow the solvent to flash off between coats You may need to apply five or six coats to hide the shadow of the repair Most gelcoats will cure lighter in color if they are too thin Most manufacturers recommend a total film thickness of 15 to 20 mils Avoid applying the gelcoat in two or three heavy coats which may cause solvent entrap ment and improper curing This may also have an effect on the color of the cured repair Mix a second batch using the 1 3 portion of gelcoat and patching additive This time use about three parts of patching additi
134. n plus about 1 25mm to leave enough room to grind the inner skin bevel For example if the inner skin is 1 4 6mm thick the bevel will extend 3 7 5cm from the edge of the hole hin a is TRS Figure 5 15 Cut back the outer skin and core several inches Figure 5 16 Grind a 12 to 1 bevel around the edge of the in from the hole through the inner skin ner and outer skins The core and outer skin should be cut back about 4 10cm from the edge of the hole through the inner skin 3 Grind a minimum 12 to 1 bevel around the inner edges of both skins to provide adequate bond ing surface when re laminating the skin repair patches Figure 5 16 4 Bond a permanent backer to the back side of the inner skin following the procedure in Section 4 2 2 The backer should match the contour of the panel 5 Laminate a new inner skin repair patch following the procedure in Section 4 3 6 Bond a new piece of core material in place against the new inner skin 7 Laminate a new outer skin repair patch following the procedure in Section 4 3 Finish the outer skin following the procedures beginning in Section 2 1 The information in Sections 2 3 4 and 5 is intended to provide a range of repair procedures for typical cored and non cored fiberglass structures Individual procedures or the sequence of pro cedures may be altered to suit your situation Keep in mind that the objectives in repairing the fi berglass structure are to restore
135. n the repair has cured it is not necessary to grind a bevel to make the repair flush with the surface With the proper fabric over lap on each side of the joint 12 times the thickness of the laminate a structural repair can be achieved without grinding a bevel Prepare both sides of the joint to achieve a good bond and apply the layers of fabric over the joint as you would if you were applying to the bevel When the epoxy has cured put the liner back in place and the repair is complete 5 3 Repairing transom delamination Removing a section of skin to expose and replace the core is a method often used to repair de laminated powerboat transoms Transoms are major structural parts of fiberglass powerboats especially outboards They not only support the weight of the motor they maintain the shape of the boat and are a mounting point for holdowns towing eyes and other accessories Outboard motors apply a considerable load to the transom The effects of the motor s weight are concentrated on small areas of the skin and core when the boat is accelerated under normal operating conditions and when the boat is bouncing along on a trailer Figure 5 8 Over time Repairing Core Related Damage 34 Figure 5 8 Motor loads are concentrated on the fi berglass skin and core where the mount is located Moisture penetrates cracks in the skin leading to dela Motor weight and mination and eventual rot of the plywood core Transom oper
136. nder pres sure into the void Figure 8 1 Fill the remaining holes in the laminate with an epoxy 404 or 406 filler mixture thickened to a mayonnaise consistency Allow the epoxy to cure thoroughly If voids are extensive use an 810 Fillable Caulking Tube with the appropriate sized drilled hole in the laminate to fill the voids If necessary use multiple applications to avoid excessive exo thermic heat buildup from filling too large a void at one time Repairing Keels and Rudders 56 Figure 8 1 Drill holes through the laminate in areas of suspected voids i z Inject the mixture into the y voids 4 Repair the lead surface if the impact was severe enough to dent or gouge the lead Follow the procedures outlined below Section 8 0 2 Apply an epoxy 406 filler mixture thickened to a mayonnaise consistency to the remaining voids in the damaged lead ballast and a thin layer of the mixture to the beveled bonding surface of the laminate 5 Apply a repair patch to the repair area following the procedure in Section 4 3 before the thick ened epoxy layer begins to gel Allow the patch to cure thoroughly Sand and fair the patch and apply several coats of epoxy to the area Wet sand the final coat after it has cured thoroughly and apply bottom paint 8 2 Repairing external ballast keels One of the advantages of using lead for an external keel in addition to its high density is its mal leability The lead will deform and thereby
137. ng fairing or applying fabrics the success of the application depends not only on the strength of the epoxy but also on how well the epoxy adheres to the surface to which it is being applied Unless you are bonding to partially cured epoxy the strength of the bond relies on the epoxy s ability to mechanically key into the surface That is why the follow ing three steps of surface preparation are a critical part of any secondary bonding operation For good adhesion bonding surfaces should be DRY SANDED 1 Clean Bonding surfaces must be free of any contaminants such as grease oil wax or mold release Clean contaminated surfaces with lacquer thinner acetone or other appropriate solvent Wipe the surface with paper towels before the solvent dries Clean surfaces before sanding to avoid sanding the contaminant into the surface Follow all safety precautions when working with solvents 2 Dry All bonding surfaces must be as dry as possible for good adhesion If necessary accelerate dry ing by warming the bonding surface with hot air guns hair dryers or heat lamps Use fans to move the air in confined or enclosed spaces Watch for condensation when working outdoors or whenever the temperature of the work environment changes 3 Sanded Sand smooth non porous surfaces thoroughly abrade the surface For most surfaces 80 grit aluminum oxide paper will provide a good texture for the epoxy to key into Be sure the sur
138. ng operation It is also applied in multiple lay ers laminated and in combination with other materials to build composite parts Fiberglass cloth may be applied to surfaces by either of two methods The dry method refers to applying the cloth over a dry surface The wet method refers to applying the cloth to an ep oxy coated surface often after the wet out coat becomes tacky which helps it cling to vertical or overhead surfaces Since this method makes it more difficult to position the cloth the dry method is the preferred method especially with thinner cloth Dry method 1 Prepare the surface as you would for bonding Section 9 4 1 2 Position the cloth over the surface and cut it several inches larger on all sides If the surface area you are covering is larger than the cloth size allow multiple pieces to overlap by approximately two inches On sloped or vertical surfaces hold the cloth in place with masking or duct tape or with staples 3 Mix a small quantity of epoxy three or four pumps each of resin and hardener 4 Pour a small pool of resin hardener near the center of the cloth 5 Spread the epoxy over the cloth surface with a plastic spreader working the epoxy gently from the pool into the dry areas Figure 9 17 Use a foam roller or brush to wet out fabric on vertical surfaces Properly wet out fabric is transparent White areas indicate dry fabric If you are apply ing the cloth over a porous surface be sur
139. nks and the like You may have to cut access holes in the hull liner or cabin sole to see the area in question Stringer damage often accompa nies sole delamination See Section 6 Fortunately you can purchase access covers to fill the holes if there is no stringer damage to repair Once you have resigned yourself to cutting holes in your boat use a mirror and flashlight and look for the following Impact damage Look for obvious fractures in the stringer Also look for delamination of tab bing and core away from the impact point Inspect the tabbing where the stringer attaches to a bulkhead or transom Rot damage W ood cores rot from water leaking around fasteners and from water collecting where the fiberglass skin has delaminated You can often tap the suspected area of stringer with a small hammer The impact of the hammer has a definite dead sound where the core is not firmly attached to the fiberglass 3 1 Repairing local core damage For small areas of rot you may be able to simply dry the stringer and inject epoxy into the rotted area While this is a common method of wood stringer repair it is not nearly as effective as re placing the damaged area with wood Without removing the skin from the wood it is often dif ficult to determine the extent of the rot and how wet the core is Also the degree of penetration of the injected epoxy cannot be accurately determined so you do not know how good your re pair is If however
140. oden Boat Restoration amp Repair An illustrated guide to restore the structure improve the appearance reduce the mainte nance and prolong the life of wooden boats with WEST SYSTEM epoxy Includes informa tion on dry rot repair structural framework repair hull and deck planking repair hardware installation with epoxy and protective coating 002 650 Gelcoat Blisters Diagnosis Repair amp Prevention A guide for repairing and preventing gelcoat blisters in fiberglass boats with WEST SYSTEM epoxy Includes an analysis of the factors that contribute to blister formation and illustrated steps for preparation drying repairing and coating for moisture protection 002 150 Vacuum Bagging Techniques A step by step guide to vacuum bag laminating a technique for clamping wood core materials and synthetic composites bonded with WEST SYSTEM epoxy Discusses the ory molds equipment and techniques used to build composite structures 002 740 Final Fairing amp Finishing Techniques for fairing wood fiberglass and metal surfaces Includes fairing tools mate rials and a general guide to finish coatings DVD 002 550 002 898 WeEsT SYSTEM Epoxy How to DVD An interactive compilation of three instructional videos Basic Application Techniques a video primer on WEST SYSTEM Epoxy Products and their use includes safety procedures and application tips for coating bonding and fair ing Fiberglass Repair with West System Brand Epoxy is a guide
141. often found in areas of solid laminate They often appear near a bulkhead deck to cabin curve or window In addition to the cosmetic surface repair a thorough repair will often require structural repair or reinforcing to reduce the flexing The longer a laminate is allowed to flex or the greater the impact the deeper the cracks The deeper a crack extends into the laminate the more the panel s strength is reduced The first step in the repair is to prepare the damaged area and assess the degree of damage Examine the pattern and location of cracks to determine their cause Figure 2 1 If the pattern or location indicates flexing examine the interior side of the panel to determine the best loca tion for additional reinforcing If the cracks are a result of impact examine the interior side of the panel to determine whether damage extends through the entire laminate Flex crackin Exterior Interior around i Impact impact bulkhead Remove any surface contaminants such as wax oil or mold release Wipe an area at least twice as large as the damaged area with a wax and silicone remover Dupont Prep Sole 3919S ace tone or other appropriate solvent Dry the area with clean paper towels before the solvent evaporates Open the cracks for repair Use a sharpened V shaped tool to scrape down to the bottom of the cracks Figure 2 2 A puncture type can opener with the tip sharpened to about 90 works well Beveling the s
142. om the ballast Although the fiberglass laminate of the keel is generally much thicker than the hull and deck laminate the procedure for the skin repair is the same as described in Section 4 Repair ground ing damage to an internally ballasted keel as follows Remove all loose and damaged material to expose solid laminate in the damaged area and if necessary expose the lead core Grind the edge of the laminate to a circular or oval shape and bevel the edge to a minimum 12 to 1 slope to provide a good bonding surface for the repair patch Wear a dust mask Inspect for any voids and moisture between the laminate and the lead ballast Tapping with a small hammer may help to reveal voids Voids between the skin and the lead can be extensive and hold a lot of water Often water will drip or seep from a crack in the bottom of a keel for some time after a boat is pulled from the water Drill Smm holes through the laminate in areas of suspected voids If water can be detected drill a pattern of holes in that area to allow the void to dry out Apply moderate heat to the area to speed drying Flushing the void with dena tured alcohol can help to remove moisture Fill all voids between laminate and the lead ballast with an epoxy 404 or 406 filler mixture thickened to a catsup consistency after the laminate and voids have been thoroughly dried Use an 807 Syringe with the tip cut back to fit the 6 Smm hole to inject the mixture u
143. ombustion can occur Clean resin or mixed epoxy residue with lacquer thinner acetone or alcohol Follow all safety warnings on solvent containers Clean hardener residue with warm soapy water Dispose of resin hardener and empty containers safely Puncture a corner of the can and drain residue into the appropriate new container of resin or hardener DO NOT dispose of resin or hardener in a liquid state Waste resin and hardener can be mixed and cured in small quantities to a non hazardous inert solid CAUTION Large pots of curing epoxy can get hot enough to ignite surrounding combustible materials and give off hazardous fumes Place pots of mixed epoxy ina safe and ventilated area away from workers and combustible materials Dispose of the solid mass only if curing is com plete and the mass has cooled Follow federal state or local disposal regulations 9 2 Epoxy products This section provides a short description of WEST SYSTEM resin hardeners and fillers Refer to the current User Manual c amp Product Guide for complete information on all WEST SYSTEM prod ucts 9 2 1 Resin and hardeners Resin 105 Resin A clear light amber low viscosity epoxy resin that can be cured in a wide temper ature range to yield a high strength rigid solid that has excellent cohesive properties and is an outstanding bonding adhesive and moisture vapor barrier Two types of WEST SYSTEM harden ers are formulated for use with 105 Resin 205 and 206 Ha
144. or bonding 5 3 3 Preparing a new transom core Prepare a new plywood core to match the shape and thickness of the core that was removed Try to use the same grade plywood or better that was used in the original core Marine grade plywood is ideal for this repair If marine grade plywood is not available use more layers of thinner AB grade exterior plywood Be sure to fill any voids in the plywood edges with thick ened epoxy after the panels are cut into shape Repairing Core Related Damage 36 When layers are installed in pieces as shown below use thinner sheets of the same type of ply wood laminated to equal the thickness of the original core For example if a 1 thick core consisted of two sheets of 34 plywood you may laminate three sheets of 1 2 or four sheets of 3 4 to equal the original 14 core thickness Trim and dry fit the new pieces of core to fit the void left by the old core Make a template of the transom and use it to layout the plywood layers Because the opening in the transom skin is smaller than the full sized plywood core you will need to replace each layer of the core in pieces Figure 5 10 Cut each layer into pieces small enough to fit through the opening in the transom skin Stagger the joints in each layer by at least eight times the plywood thickness from joints in the adjoining layers For example a 3 stagger will be required between joints when using plywood Ideally these joints are staggered w
145. ot resolve the problem call the West System technical staff POSSIBLE CAUSES Off ratio too much or too little hardener will affect the cure time and thoroughness of the cure Low temperature Epoxy mix tures cure slower at low tem peratures Insufficient mixing Incorrect products Insufficient cure Resin starved joint epoxy has wicked into porous bonding surfaces Contaminated bonding surface Bonding area too small for the load on the joint Too much clamping pressure squeezed epoxy out of the joint Moisture from condensation or very humid conditions reacts with amines in uncured hard ener Entrapped air from aggressive roller application Amine blush forms as a result of the curing process Moisture in contact with hard ener and metal container PREVENTION 1 Remove epoxy Do not apply additional material over non curing epoxy See 9 3 5 Removing epoxy 2 Check correct number of pump strokes use equal strokes of resin and hardener DO NOT add extra hardener for faster cure 3 Check for correct pump 5 1 or 3 1 ratio 4 Check pump ratio Be sure pumps are operating and metering resin and hardener properly see pump instruc tions 1 Allow extra curing time in cool weather 2 Apply heat to maintain the chemical reaction and speed the cure 3 Use a faster hardener designed to cure at lower tem peratures See 9 3 2 Understanding and controlling cure time 1 Remove epoxy Do not
146. ough the opening using the string to keep it from dropping Note Grind the hole and trim the backer to an oval shape rather than a round shape An oval shape will allow the narrower dimension of the oversized backer to pass through the wider di mension of the smaller hole without having to flex the backer Bond the backer in place with a quick setting adhesive like G 5 Five Minute Adhesive available from West System Apply adhesive to the inside edge of the hole and to the edge of the laminate A thickened epoxy high density filler mixture will work if a quick curing adhesive is not available Pull the backer into position on the inside of the panel and tie off the strings to a stationary ob ject close to the hole or a stick laid across the hole Figure 4 4 Keep enough tension on the strings to hold the backer in position and bend the backer as necessary to match the contour of the panel Some of the epoxy mixture should squeeze out of the joint Scrape away the excess and smooth the joint before it begins to cure Allow the epoxy to cure thoroughly before removing the screws Proceed with laminating the repair patch as described in Section 4 3 The method just described works well on compound curved sections or corners In many smaller or flat areas other material like plastic laminate can work as a backer as long as the patch holds the proper panel shape until it cures 25 Repairing Damaged Skins If you intend to vacuum bag th
147. ough tooth for good adhesion Follow the coating manufacturer s rec ommendation for surface preparation Wet sanding is preferred by many people because it re duces sanding dust and it will allow you to skip Step 2 Wet sanding is often used for final sanding after an initial machine sanding with a coarse grit 4 After you are satisfied with the texture and fairness of the surface rinse the surface with fresh water Rinse water should sheet evenly without beading or fish eyeing If rinse water beads up a sign of contamination wipe the area with solvent and dry with a paper towel then wet sand again until beading is eliminated Proceed with your final coating after the surface has dried thoroughly To reduce the possibility of contamination it is a good idea to begin coating within 24 hours of the final sanding Follow all of the instructions from the coating system s manufacturer It may be a good idea to make a test panel to evaluate the degree of surface preparation required and the compatibility of the finish system E 79 Estimating guides for WEST SYSTEM products Appendix A Estimating guides for WEST SYSTEM products Group size quantities and coating coverage WEST SYSTEM epoxy resin and hardeners are packaged in three Group Sizes For each container size of resin there is acorresponding sized container of hardener and a corresponding mini pump size When purchasing resin hardener and mini pumps be sure all contain
148. pair procedures can be com pleted with a small inventory of common or readily available hand and power tools The tools listed here are specially suited for repair procedures in this manual or for working with epoxy Grinders Grinding to remove damaged laminate and pre paring an area for bonding is a key step in many of the procedures throughout this manual The proper grinder can make a big difference in the quality and efficiency of these operations We recommend using a 7 polisher about 2000 RPM with an 8 diameter 1 2 thick foam sand ing pad attached Use 36 50 grit paper either self adhesive or at tached with feathering disc adhesive for quick removal or general shaping Use 80 grit for finer shaping and smoothing Fairing boards A long flexible sanding block is the primary tool for overall fairing Working onthe same principle as a batten it will bend to the overall shape of the surface bridging the low areas and knocking down the high spots A long fairing block can be made of 14 to 2 plywood depending on the curve of the surface to be faired The length of the block is a multiple of 11 to make economical use of a9 x 11 sheet of sandpaper The width of the block is 4 2 or half a sheet The sandpaper is applied to the block with feathering disc adhe sive Handles may be bonded to the ends of the block for greater control Roller cover brushes Roller cover brushes are made by cutting WEST SYSTEM 800
149. passes from a liquid state through a gel state to a Solid solid state Finalcure phase Cure time ts shorter when the epoxy is warmer lt N RECOAT Cure time is longer when the epoxy is cooler be _ o Q z FE gt x lt O Q LI Minimum Recommended Temperature Cure time after mixing The mixture will become tack free about midway through the initial cure phase While it is still tacky a new application of epoxy will still chemically link with it so the surface may still be bonded to or recoated without special preparation However this ability diminishes as the mix ture approaches the final cure phase 3 Solid Final cure phase The epoxy mixture has cured to a solid state and can be dry sanded and shaped You should not be able to dent it with your thumbnail At this point the epoxy has reached about 90 of its ulti mate strength so clamps can be removed It will continue to cure over the next several days at room temperature A new application of epoxy will no longer chemically link to it so the surface of the epoxy must be properly prepared and sanded before recoating to achieve a good mechanical secondary bond See 9 4 1 Surface Preparation 9 3 2 Understanding and controlling cure time Open time and cure time govern much of the activity of building and repairing with epoxy Open time dictates the time available for mixing application smoothing shaping assembly and
150. pect the condition of the plywood core material If the plywood is sound but wet you may be able to dry it thoroughly and re bond the skin Section 5 3 1 Fill any minor voids or delaminations or end grain in the dried core while it is uncovered Drying a saturated transom core may be difficult even with heaters or heat guns Unless you have plenty of time to allow for drying you are better off replacing all the core If however the plywood has deteriorated or dry rot has set in the plywood should be replaced Even if the core damage is isolated to some portion of the transom you may want to consider replacing all of the plywood core rather than repairing it Remove skin ieee Figure 5 9 Cut through the outer skin at the perimeter of the core Remove the skin and the core if it is de laminated or rotted Remove damaged core Remove the damaged plywood core Figure 5 9 Use a chisel or whatever combination of tools you need to remove all damaged material The plywood core in the perimeter and corners of the transom will be the biggest challenge If necessary use large drill bits to carefully weaken and re move stubborn areas Rotary rasps can also be effective Home made tools similar to a grub hoe or an adz can be used to remove the stubborn perimeter areas Shave all traces of the core mate rial from the inner skin being careful not to damage the skin Make any necessary repairs to the inner skin Sand the skin to prepare f
151. products 9 3 Handling epoxy 9 4 Basic techniques Appendix A Estimating guides for WEST SYSTEM products B Tools i Sa C Cold temperature bondi ana soning ecni D Problem solving guide Index NO Oo f 10 12 12 13 16 21 21 22 25 28 28 31 33 39 42 42 44 47 48 49 52 54 54 55 55 56 57 59 61 61 62 64 69 79 80 81 83 86 1 Introduction 1 Introduction Over the last several decades the popular perception of fiberglass boats is that they are mainte nance free and far more durable than the wooden boats that preceded them While fiberglass boats do on average require less maintenance they are not without problems In addition to the usual damage from collisions groundings and the forces of nature fiberglass boats also suf fer from many of the same age related problems of fatigue and moisture that have long been as sociated with older traditionally built wooden boats This manual provides repair and maintenance solutions to many of the problems that afflict fi berglass boats 1 1 Typical fiberglass boat construction A fiberglass boat is a composite structure made of many layers of various reinforcing fabrics and core materials bonded together with plastic resins You could also look at it as a plastic resin shell reinforced with various fibers or Fiber Reinforced Plastic FRP Most loads in the structure are carried by the fibers in the laminate Resin and core materials s
152. r it is to keep it even and avoid runs or sags in each coat Finish the area with long light even strokes to reduce roller marks Overlap the previously coated area to blend both areas together Coat as many of these small working areas as you can with each batch If a batch begins to thicken before it can be applied discard it and mix a fresh smaller batch Cut cover into segments to make tipping brush Figure 9 23 Apply the epoxy in thin even coats us Figure 9 24 Tip off the fresh coat of epoxy with ing a thin foam roller the grain using a foam roller brush to remove bub bles and roller marks Drag a foam roller brush lightly over the fresh epoxy in long even overlapping strokes after each full batch is applied Use enough pressure to smooth the stipple but not enough to remove any of the coating Figure 9 24 Alternate the direction in which each coat is tipped off 1st coat vertical 2nd coat horizontal 3rd coat vertical etc A WEST SYSTEM 800 Roller Cover can be cut into segments to make a tipping bush Apply second and subsequent coats of epoxy following the same procedures Make sure the previous coat has cured firmly enough to support the weight of the next coat To avoid sanding between coats apply additional coats before the previous coat has become completely tack free and apply all of the coats in the same day See Special preparation Cured epoxy in Section 9 4 1 After the final coat has cured overnight wash
153. rdeners require a 5 part resin to 1 part hardener mixing ratio 207 and 209 Hardeners require a 3 to 1 mixing ratio Hardeners 205 Hardener Used for general bonding barrier coating and fabric application Formulated to cure at lower temperatures and to produce a rapid cure that develops its physical properties quickly at room temperature 5 1 mix ratio 206 Slow Hardener Used for general bonding barrier coating and fabric application For mulated for a longer working and cure time or to provide adequate working time at higher tem peratures 5 1 mix ratio 63 Using WEST SYSTEM Epoxy Note 205 Fast and 206 Slow Hardener may be blended for intermediate cure times Always maintain the proper 5 part resin to 1 part hardener ratio Do not mix 205 or 206 5 to 1 ratio Hardeners with 207 or 209 3 to 1 ratio Hardeners 207 Special Coating Hardener Formulated specifically for barrier coating and fabric appli cation where clear finish is desired 207 contains a UV stabilization additive but still requires long term UV protection with paint or varnish It provides good physical properties for bond ing but it is more difficult to thicken and less cost effective for this purpose than 205 or 206 hardener 207 is a light amber color that will tint wood slightly darker and warmer similar to varnish 3 1 mix ratio 209 Extra Slow Hardener Used for general bonding barrier coating and fabric application in extremely warm and or hu
154. rial as you can from the surface using a stiff metal or plastic scraper warm the epoxy to lower its viscosity Clean the residue with lacquer thinner acetone or alcohol Fol low safety warnings on solvents and provide adequate ventilation After recoating wood sur faces with epoxy it s a good idea to brush the wet epoxy in the direction of the grain with a wire brush to improve adhesion Allow solvents to dry before recoating Removing fiberglass cloth applied with epoxy Use a heat gun to heat and soften the epoxy 9 Start in a small area near a corner or an edge Apply heat until you can slip a putty knife or chisel under the cloth about 200 F Grab the edge with a pair of pliers and pull up on the cloth while heating just ahead of the separation On large areas use a utility knife to score the glass and re move in narrower strips Resulting surface texture may be coated or remaining epoxy may be removed as follows Removing cured epoxy coating Use a heat gun to soften the epoxy 200 F Heat a small area and use a paint or cabinet scraper to remove the bulk of the coating Sand the surface to remove the remaining material Provide ventilation when heating epoxy 69 Using WEST SYSTEM Epoxy 9 4 Basic techniques The following basic techniques are common to most repair or building projects regardless of the type of structure or material you are working with 9 4 1 Surface preparation CLEAN Whether you are bondi
155. rinkles trapped air and excess epoxy My d FH a 12 to 1 bevel my j k1 1 i a ee Fiberglass fabric bt 39 Repairing Core Related Damage 6 Wet out and apply each of the remaining fabric layers with epoxy ending with the smallest piece Apply each layer before the previous layer becomes tack free Smooth each layer with a plastic spreader to remove wrinkles trapped air and excess epoxy Figure 5 12 7 Apply several coats of epoxy over the fabric to fill the weave of the fabric when the epoxy has reached a gel stage Use the thin foam roller to apply each coat after the previous coat reaches its gel stage and before it becomes completely tack free to avoid sanding between coats Allow the final coat to cure thoroughly 8 Wash and sand the final coat after it has cured thoroughly Sand and fair in the edges of the fab ric to blend with the hull surface Any flaws or unevenness can be faired with a thick mixture of epoxy and 407 or 410 Fairing Filler Seal filled and sanded surfaces with epoxy and wet sand to prepare the surface for paint Be sure to coat and seal the end grain of all holes drilled through the transom with multiple coats of epoxy This is not a waste of time If the holes are not properly sealed plan on replacing the core again in the future If all sources of water are eliminated by sealing the wood in epoxy the repair should be better than new and last indefinitely Remember to coat screw holes wit
156. rs with WEST SYSTEM epoxy is not recommended Disposable thin urethane foam rollers such as WEST SYSTEM 800 Roller Covers allow you greater control over film thickness are less likely to cause the epoxy to exotherm and leave less stipple than thicker roller covers Cut the covers into narrower widths to reach difficult areas or for long narrow surfaces like stringers Complete all fairing and cloth application before beginning the final coating Allow the temper ature of porous surfaces to stabilize before coating Otherwise as the material warms up air within the porous material may expand and pass from the material outgassing through the coating and leave bubbles in the cured coating 1 Prepare the surface as necessary Section 9 4 1 2 Mix only as much resin hardener as you can apply during the open time of the mixture Pour the mixture into a roller pan as soon as it is mixed thoroughly 77 Using WEST SYSTEM Epoxy 3 4 Recoating Load the roller with a moderate amount of the epoxy mixture Roll the excess out on the ramp part of the roller pan to get a uniform coating on the roller Roll lightly and randomly over an area approximately 2 X 2 to transfer the epoxy evenly over the area Figure 9 23 As the roller dries out increase pressure enough to spread the epoxy into a thin even film In crease the coverage area if necessary to spread the film more thinly and evenly The thinner the film the easie
157. rt of the day 2 Apply a thinner coat allowing air to escape easier 3 Tip off the coating with a roller cover brush to break bubbles After applying epoxy with an 800 Roller Cover force ep oxy into pinholes with a stiff plastic or metal spreader held at a low or nearly flat angle Recoat and tip off after all pin holes are filled 1 Be sure mixing equipment is clean Avoid waxed mixing containers 2 Be sure surface is properly prepared Use proper grit sandpaper for the coating e g 80 grit for epoxy See paint or varnish manufacturer s instructions for proper sur face preparation After surface is prepared avoid contamination finger prints exhaust fumes rags with fabric softener silicone Coat within hours of preparation After wet sanding rinse water should sheet without bead ing beading indicates contamination Wipe with appro priate solvent and re rinse until water no longer beads Contact the West System technical staff if you have addi tional questions 85 Index A abrasion 6 active core 10 additives 63 68 adhesive fillers 63 aluminum bonding to 70 B backing support 23 barrier coating 76 bevel 13 bonding basic technique 70 fasteners 48 hardware 49 preparation 69 to metal 49 with fillets 72 bottom paint 9 cabin sole 10 casting epoxy base 52 chopped strand mat 1 clamping 72 cleanup 62 cockpit sole 10 cold temperature bonding 81 construction
158. s for the repair of hardware installations with the objective of improving the load car rying ability of the hardware and eliminating hardware movement and leaks Standard hardware installations Many factory hardware installations are inadequate for the loads on the hardware which is evi dent if the installation is loose or leaking Hardware items attached with multiple fasteners must have all of the mounting holes drilled precisely or the fasteners will not share the load equally If not drilled accurately the hole with the most highly loaded fastener will elongate as the hard ware is continually loaded The hardware eventually becomes loose and the gap provides an entrance point for moisture The typical approach to this problem is to accept the hardware movement and to bed the hard ware item in an elastic sealant material A variety of sealants are used for this purpose all witha very high elongation capability usually 200 or greater and good adhesive qualities Unfortu nately high elongation means low load carrying capability and the inability to prevent hard ware from moving when subjected to any significant load The sealant s job is limited to preventing water leakage However over time continual hardware movement will break down sealant material eventually allowing moisture to pass through into the laminate Improved hardware installations To overcome the problems associated with hardware installations West System has dev
159. s necessary to bridge gaps in the joint the thinner the mixture the more it can penetrate the surface and that you do not use this method for highly loaded joints or for bonding end grain or other porous surfaces Laminating The term laminating refers to the process of bonding numbers of relatively thin sheets like plywood veneers fabrics or core material to create a composite A composite may be any num ber of layers of the same material or combinations of different materials Methods of epoxy ap plication and clamping will differ depending on what you are laminating Because of large surface areas and limitations of wet lay up time roller application is the most common method for applying epoxy A faster method for large surfaces is to simply pour the resin hardener mixture onto the middle of the panel and spread the mixture evenly over the sur face with a plastic spreader Apply thickened mixtures with an 809 Notched Spreader Using staples or screws is the most common method of clamping when you laminate a solid ma terial to a solid substrate An even distribution of weights will work when you are laminating a solid material to a base that will not hold staples or screws such as a foam or honeycomb core material Using WEST SYSTEM Epoxy 72 Vacuum bagging is the ideal clamping method for laminating a wide range of materials Through the use of a vacuum pump and plastic sheeting the atmosphere is used to apply per fectly
160. s reused the same bevel is required on each side of the cut after the skin is re bonded to the new core Layout the cut line on the transom the required distance from the corners Measure from the end of the rounded corners where they blend into the flat transom surface 35 Repairing Core Related Damage 5 3 2 Removing the damaged skin and core The skin removal method as described above for deck or hull panel delamination is essentially the same for transom delamination Often if the core has been wet for a period of time the ply wood veneers will begin to delaminate and much of the veneer may have rotted away Remove the outer or inner transom skin and plywood core as follows Cut through the skin at the cut line established by the bevel length Use a panel or circular saw with a carbide tipped plywood blade or a router with a small diameter straight fluted bit Set the blade or bit to the depth of the skin only Remove the skin The skin should separate easily in areas where the core is damaged or wet In areas where the skin is well bonded to the core use a chisel or thin blade between the skin and core to pry the skin away from the core material Applying heat to the joint with a heat gun can help to soften the skin core bond Be careful not to overheat the skin Avoid damaging the skin by over bending or using too much force when prying the skin from the core It is worth the ef fort of getting it off in one piece Ins
161. s seldom any fiberglass or resin coating to seal the back side of the plywood so moisture also enters the plywood from below the sole where the air is often damp and stagnant When the plywood begins to delaminate the deck will feel spongy underfoot This is discom forting and unsafe to walk on and also reduces the athwartship side to side hull stiffness the sole would normally provide If not repaired the plywood will rot This situation can be avoided if the builder takes care to seal any penetrations into the plywood If moisture damage is severe enough replacing the affected plywood is often necessary The fol lowing procedure describes sole replacement in a runabout A pontoon deck would be repaired in much the same way but it will usually be fastened with screws around perimeter framing 6 1 1 Removing the damaged sole 1 2 Remove any equipment or hardware screwed down to the sole This may include things like seat bases cooler brackets and step or ladder brackets Pull up any carpeting or covering to expose the fasteners or tabs used to hold the plywood down on top of the frame and stringer system If there are cutouts in the sole for access to storage com partments below carefully remove any trim around the cutout You will probably want to reuse that once the new sole is in place Before cutting tabs or removing any of the fasteners make sure the hull is supported so that its sides do not move once the sole is no lon
162. s to exotherm heat up quickly move it outdoors Avoid breathing the fumes Do not dispose of the mixture until the reaction is complete and has cooled 9 3 4 Adding fillers and additives Fillers Figure 9 6 Epoxy can be thickened to the ex act consistency needed for a particular job The procedures in this manual refer to four common consistencies syrup catsup mayon naise and peanut butter Unthickened Slightly thickened Moderately thickened Maximum thickness CONSISTENCY SYRUP CATSUP MAYONNAISE PEANUT BUTTER GENERAL APPEARANCE Drips off vertical Sags down vertical Clings to vertical Clings to vertical CHARACTERISTICS surfaces surfaces surfaces surfaces Peaks fall over Peaks stand up Coating wetting out Laminating bonding flat General bonding Gap filling filleting USES before bonding applying panels with large filleting hardware fairing bonding uneven fiberglass graphite and other fabrics surface areas injecting with a syringe bonding surfaces Using WEST SYSTEM Epoxy 68 After selecting an appropriate filler for your job Section 9 2 2 use it to thicken the epoxy mix ture to the desired consistency The thickness of a mixture required for a particular job is con trolled by the amount of filler added There is no strict formula or measuring involved use your eye to judge what consistency will work best Figure 9 6 gives you a general guide to the differences betw
163. se of feel especially important to a helmsman if the boat is raced Most stock rudders simply bear on the inside of the fiberglass housing in which the metal rudder shaft turns Figure 8 8 Some builders use Delrin plastic or a similar material as an insert for lower friction and better wearing performance But the high loads exerted by the rudder even tually wear out the bearings This section describes how to restore tight steering control by in jecting a new long wearing epoxy graphite bearing surface around the rudder shaft The amount of slop in the rudder bearings is most easily detected when the boat is out of the wa ter Grab the bottom of the rudder blade and wiggle it side to side Look for excess lateral mo tion of the rudder blade and listen for the thump of the shaft hitting the opposite side of the bearing as the rudder is wiggled Careful observation will show if the movement is coming from the lower upper or both bearing points Repairing Keels and Rudders 60 w Waxed rudder shaft Rudder shaft y Bearing Shaft housing wear points Shaft housing Ae 7 jee E Hull Aw 3 6 5 mm holes Detail Figure 8 9 pa A i iS New bearing pad Ca P e 34 1 diameter A Rudder Fa aF F j 807 Syringe with epoxy 406 423 Graphite mixture Figure 8 8 Most stock rudders simply bear on the inside ofa Figure 8 9 Inject enough of epoxy 406 423 mixture through fiberglass housing and the high loads exerted by
164. sent try to duplicate it Locate new stringers as close as possible to their original position This is especially true of engine string ers or stringers that support other equipment Support the hull If major stringer replacement is necessary be sure to support the hull well so the original shape is maintained Stringers that are removed or have broken away from the hull may allow parts of the hull to sag 3 3 Replacing active core sections Often damage to the core of a stringer is limited to a small section or the stringer may be too dif ficult to remove You may be able to replace only the damaged portion restoring the strength of the stringer while leaving it in position in the boat Because the wood in wood cored stringers is structural any repairs you make to it have to be joined with a proper scarf If you are replacing a section of plywood stringer use a minimum of an 8 to 1 scarf bevel For a 4 thick piece of plywood this equates to a 6 long bevel When re pairing hardwood or highly loaded core areas use a longer 12 to 1 scarf angle When cutting 13 Repairing Stringers and Floor scarfs keep in mind the longer the scarf angle the greater the joint surface area the stronger the joint All joints in fiberglass skins should have a minimum 12 to 1 bevel or overlap Forming the scarf bevel on the new piece of wood is fairly easy You can use typical cutting tools with the piece of wood supported on a work bench Cutting
165. sistency of catsup 4 Inject the epoxy mixture under the skin through each of the holes starting in the center of the delaminated area Figure 5 3 The shortened tapered syringe tip will fit tightly in the 6 A2 Smm holes You should be able to develop enough pressure to force the epoxy to the sur rounding holes 5 Clamp the skin to the core when you are sure you have injected enough epoxy to bridge any gaps between the skin and core Use evenly placed weights or braces covered with plastic to hold the skin tight and fair against the core Sheet metal or drywall screws will also work Whichever clamping method you use don t distort the panel by applying too much pressure You only need to keep the skin fair and keep the skin and core in contact while the epoxy cures Remove the excess epoxy before it begins to gel Allow the epoxy to cure thoroughly before removing clamping 31 Repairing Core Related Damage Figure 5 3 Inject the epoxy mixture under the skin through Figure 5 4 Fill any remaining voids and fair the surface with each of the holes starting in the center of the delaminated an epoxy 407 mixture area Fill all voids between the skin and core 6 Sand the surface and fill any remaining holes with an epoxy 407 low density filler mixture thickened to the consistency of peanut butter Figure 5 4 After the epoxy has cured thor oughly sand the surface fair and finish it as described in Section 2 For thin skins this pro
166. ss fabric to the inner side of the panel Bond the core in place as follows Prepare the surface for bonding Remove any traces of contamination by wiping the surface with solvent and drying with paper towels before the solvent evaporates Use a degreaser or de tergent in areas that may be contaminated with gasoline or oil residue before wiping with sol vent Use a stiff nylon bristle brush on heavily textured surfaces like roving Abrade the bonding surface by sanding with 50 grit sandpaper and brush the area free of dust or loose material Use a wire brush to abrade heavily textured surfaces The bonding surface should appear dull Prepare the core material and fabric Cut the core material to size Round the corners and bevel the edges of the core material to reduce stress concentrations Cut four or five pieces of fiber glass cloth each piece an inch or two shorter on each side than the one before The smallest piece of fabric should overlap the core material by 2 Scm on each side Figure 3 6 Figure 3 6 End grained balsa or high density foam core ma terial is useful for reinforcing large panel areas 4 Wet out the core and panel bonding surfaces with resin hardener mixture Apply an epoxy adhesive filler mixture thickened to the consistency of mayonnaise to the bonding surface of the core material Place the core in position on the panel to be reinforced Use enough clamping pressure to hold the piece in plac
167. t The outside edge of the bevel should be short of the corner as described earlier in Section 5 3 1 Planning the repair Laminate a re pair patch over the joint to restore skin continuity Figure 5 11 The bevel will provide a re cessed bonding area for the application of fiberglass fabric and allow the patch to be faired flush with the surface The procedure for patching the joint are the same as repairing damaged skins Follow the procedure described in Section 4 3 Limit the patch and finishing to the transom side of the corners 5 3 6 Laminating a new transom skin If your fiberglass skin is unusable plan to laminate a new fiberglass skin over the core with mul tiple layers of fiberglass and epoxy Apply enough layers to equal the same thickness as the origi nal skin See the fabric thickness chart in Appendix A Layers can be applied immediately or while the previous layer is still tacky If the epoxy is allowed to cure beyond being tacky allow it to cure overnight then wash the surface with water and sand the surface to prepare it for more layers Laminate the new skin so it extends to the edge of the 12 to 1 bevel that was machined earlier on the outer edges of the transom Install the biggest patch first with each layer being progressively smaller to fill the 12 to 1 bevel For additional information on laminating a large new fiberglass skin see Section 4 3 1 Grind a 12 to 1 bevel around the remaining edge of the transom The outsid
168. t for the repair patch by bonding a thin backer to the back of the panel from the outside of the panel The backing will become a permanent part of the panel Although the installation method and backing material can be altered depending on the size and curve of the repair area the method described below can accommodate the widest range of openings This type of back ing may also be applied from the back of the panel if you have access and the permanent backing on the interior of the panel is not objectionable The first part of this method describes laminating a backer to match a specific opening The sec ond part describes slipping the backer through the hole and bonding it in place on the back of the panel Laminating a backing support 1 Select and tape off an area of the panel next to and several inches larger than the hole opening to act asa mold for the lay up of the backing Mask the area outside of the tape to protect from ep oxy spills Apply a liberal coat of automobile paste wax or release agent to the mold area The selected area should match the curve or contour of the repair area 2 Cut two pieces of 6 oz 203g sq m fiberglass fabric the size of the waxed area Add one piece of cloth for every 12 increase in hole diameter over 12 Lay the cloth on a plastic protected work table Repairing Damaged Skins 24 Figure 4 3 Smooth the wet out fabric against the waxed panel Figure 4 4 Pull the backer tight against the inside of t
169. tabbing onto them in the same manner 15 Repairing Stringers and Floor WEST SYSTEM 738 Fabric is ideal for stringer repairs It yields about 0 040 per layer in a hand lamination so you will need fewer layers of cloth to achieve the necessary thickness for most stringers Fewer layers of fabric translates into less labor to install it There is however nothing wrong with using a lighter fabric It will require more layers per unit of laminate thickness and thus more time to install it Structurally there is little difference between 5 layers of 24 oz fab ric or 10 layers of 12 oz fabric Preparing surfaces for bonding Surface preparation for bonding 1s a critical part of any repair The bilge of a boat can be very difficult to prepare for bonding because it is likely to be contaminated especially around en gines and many areas may be inaccessible Use a degreaser or detergent in areas that may be contaminated with gasoline or oil residue be fore wiping with solvent Use a stiff brush on heavily textured surfaces like roving Remove any traces of contamination by wiping the surface with solvent and drying with paper towels before the solvent evaporates Use a 50 grit grinding disc to prepare the surface A 50 grit disc cuts quickly with little heat build up If gelcoat is present and it is soundly attached you do not need to remove it Grind it to create a fresh no gloss surface Brush the area free of dust or loose material Use a
170. tch begins to gel Figure 9 18 Drag the spreader over the fabric using even pressured overlapping strokes Use enough pressure to remove ex cess epoxy that would allow the cloth to float off the surface but not enough pressure to create dry spots Excess epoxy appears as a shiny area while a properly wet out surface appears evenly transparent with asmooth cloth texture Later coats of epoxy will fill the weave of the cloth a Figure 9 19 Trim excess cloth after the epoxy has be gun to gel using a sharp utility knife 8 Trim the excess and overlapped cloth after the epoxy has begun to gel using a sharp utility knife Figure 9 19 Trim overlapped cloth if desired as follows a Place a metal straightedge on top of and midway between the two overlapped edges b Cut through both layers of cloth with a sharp utility knife Figure 9 20 Figure 9 20 Trim overlapping fabric using a metal Figure 9 21 Remove the topmost trimming Then straightedge and a sharp utility knife for a flush lift the opposite cut edge to remove the overlapped butt joint trimming c Remove the topmost trimming and then lift the opposite cut edge to remove the overlapped trimming Figure 9 21 d Re wet the underside of the raised edge with epoxy and smooth into place The result should be a near perfect butt joint eliminating double cloth thickness A lapped joint is stronger than a butt joint so if appearance is not important you may want to
171. ted Figure 3 5 Cut each of the remaining pieces 1 4 each side narrower than the previ ous one Squeegee any excess epoxy from the surface but make sure the entire piece of fabric has been saturated Step fabric back a 1 each layer 7 Thickened epoxy to Ap fill rough surface Repairing Stringers and Floor 16 4 Apply each successive piece of fabric in the same manner Successive pieces may be applied im mediately after the previous piece or any time before the previous piece becomes tack free The fabric edges should be stepped with the last piece extending about 13 4 to 21 4 from each side of the stringer depending on the number of fabric layers Allow the lay up to reach its initial cure 5 Apply two or three coats of epoxy to fill the weave of the cloth To avoid sanding between coats apply each coat before the previous coat becomes tack free Allow the final coat to cure thor oughly Note The final two or three coats may be tinted with WEST SYSTEM 501 white or 503 gray pigment or with 420 Aluminum Powder gray or 423 Graphite Powder black If you desire a smoother cosmetic finish the lay up may be faired and finished When your repair is complete you will have a little additional finishing work to do Fiberglass repairs inevitably have some sharp edges or sharp hairs sticking out These make cleaning the bilge difficult if not downright dangerous Use 80 grit sand paper to eliminate imperfec
172. tener holes to contain the epoxy 7 Wet out the deck surface the inside of the fastener holes the fastener threads and the sanded contact surface of the hardware with epoxy While the hardware contact surface is still wet abrade the coated surface with coarse sandpaper working the epoxy into the metal surface This technique exposes fresh metal directly to the epoxy without any air contact and the possi bility of oxidation The 860 Aluminum Etch Kit can be used to treat aluminum fittings before they are wet out Insert the fasteners in the hardware 8 Apply an epoxy 404 or 406 filler mixture thickened to a peanut butter consistency to one of the bonding surfaces Apply enough of the mixture to bridge any gaps between the two surfaces Apply the thickened mixture to both the fastener threads and the inside of the fastener holes Apply enough thickened epoxy to the contact surface of the backer plate to bridge gaps between the backer and the inner surface of the panel Since the backer plate is held in compression its bond to the inner side of the panel is not critical However filling the gaps between the surfaces with epoxy will provide uniform bearing against the panel 9 Place the hardware item in position on the surface carefully inserting the bolts through the fas tener hole Have your helper on the inside of the panel cut an X through the tape over the fas Figure 7 4 Tighten the nuts until epoxy begins to squeeze from the s
173. teners vary depending on the type of fastener the substrate the loads on the fastener and any existing damage to the substrate This section describes simple fastener bonding for several situations Section 7 2 describes more ad vanced fastener bonding in combination hardware base bonding Basic fastener bonding Normal vibration can cause hardware fasteners to loosen as fibers around the fasteners are frac tured and compressed A simple countermeasure is to 1 Remove the loose fastener 2 Clean the threaded hole with a cotton swab and solvent such as acetone to remove any wax oil or other contaminate 3 Wet out the hole with epoxy using a syringe pipe cleaner or cotton swab 4 Reinstall the fastener The fastener can be waxed for easier removal This technique will help retain the strength of the connection and prevent moisture penetra tion Fastener connections that have lost strength or were under engineered require a more ex tensive repair 7 1 1 Bonding fasteners to non cored panels Hardware fasteners that are screwed to a non cored panel without additional blocking rely en tirely on the skin for holding power If the fastener hole is stripped the skin will provide little holding power for clamping or the hardware loads Panels with back access Blocking bonded to the back of the panel will not only provide the holding power for clamp ing but greatly increase the load carrying capability of the hardware If yo
174. the rudder the drilled X 5 mm diameter ports to form a 3 4 1 diame eventually wear out the bearing surfaces ter pad between the shaft and housing at each port 1 Lower the rudder from the boat and wipe the shaft with solvent to remove grease and oil In spect the shaft for roundness and straightness IMPORTANT If the shaft is out of round or bent you may need to take it to a machine shop to make it true Look for burrs rough spots or grooves Sand smooth any burrs or other rough spots on the shaft with emery cloth or very fine sandpaper The smoother the surface of the shaft the less it will abrade the bearing surface If scores or similar flaws are too deep to sand out fill them with an epoxy 406 Colloidal Silica mixture following the procedures for bonding to metal as discussed in Section 7 2 Wipe the upper and lower bearing surfaces with solvent to remove all traces of grease or oil Sand the bearing surfaces with coarse sandpaper Drill three equally spaced 36 5 mm diame ter holes through the shaft housing Figure 8 9 at the level of the bearing surfaces These ports will permit injection of the thickened epoxy to form the new bearing surfaces Cut the end of an 807 Syringe to wedge tightly into the 3 holes This will allow you to inject the thick ened mixture under pressure into the gap between the shaft and the bearing surface 3 Wax the shaft surface with three coats of automotive paste wax to act as a release a
175. their tighter weave results in a higher fiber to resin ratio which can result in a repair that is actually stronger than the original panel As a general rule the bonding area of the repair patch should be 12 times the thickness of the damaged skin on each side of the damage To maintain the necessary bonding area and keep the repair flush with the surface the edges of the repair area are beveled to a 12 to 1 angle and each piece of repair fabric is cut progressively smaller The bevel provides the proper bonding area and also allows the patch to be bonded below the surface where it can be faired flush with the surface 4 1 Assessing and preparing the damaged area Begin with a thorough inspection of the damaged area to determine the depth and extent of the repair required If accessible examine the back of the panel An abrasion or flex crack that ex tends into the roving layers will affect the skin s strength even if the damage does not extend Repairing Damaged Skins 22 completely through the laminate Cracks that are visible on the back side of a panel indicate that the fibers running through the area have lost their ability to carry their load and are structurally the same as a hole through the panel Be sure to inspect internal structural members and hard ware too An impact can cause panels to flex inward enough to damage adjoining bulkheads or frames Check for excessive flexing or panel movement If movement is evident reinforce th
176. thness of the surface sliding against it E 61 Using WEST SYSTEM Epoxy 9 Using WEST SYSTEM Epoxy This section is designed to help you understand and safely handle WEST SYSTEM epoxy prod ucts and to provide the basic techniques used in most repair and building operations Refer to the WEST SYSTEM User Manual amp Product Guide for more complete product information 9 1 Epoxy safety Epoxies are safe when handled properly To use WEST SYSTEM epoxies safely you must under stand their hazards and take precautions to avoid them Hazards The primary hazard associated with epoxy involves skin contact WEST SYSTEM resin may cause moderate skin irritation WEST SYSTEM hardeners are corrosive and may cause severe skin irri tation Resins and hardeners are also sensitizers and may cause an allergic reaction similar to poison ivy Susceptibility and the severity of a reaction varies with the individual Although most people are not sensitive to WEST SYSTEM Resins and Hardeners the risk of becoming sen sitized increases with repeated contact For those who become sensitized the severity of the re action may increase with each contact The hazards associated with resins and hardeners also apply to the sanding dust from epoxy that has not fully cured These hazards decrease as resin hardener mixtures reach full cure Refer to product labels or Material Safety Data Sheets for specific product warnings and safety information Precautions 1
177. tion have good gloss retention and a durable abrasion resistant surface provided you follow the manufacturer s instructions carefully Light colors especially white are recom mended over dark colors White reflects UV and infrared radiation better than other colors and all other things being equal outlasts other colors Polyurethanes adhere well to fiberglass sur faces bonded with both polyester and epoxy resins Note seal all areas of sanded 407 and 410 fairing compound with epoxy before applying primers or paints It is possible to color match small areas particularly if they are in fairly inconspicuous locations However if you have a large repair or several smaller repairs over a large area you may find it easier to repaint the entire hull or deck Polyurethanes just like epoxies are affected by moisture contamination This means use cau tion when painting don t paint early in the morning or late in the afternoon Also avoid paint ing in direct sunlight If you ve chosen to paint you will probably be painting the entire hull deck or cabin top Begin by inspecting the entire surface Wipe with a silicone and wax remover such as DuPont Prep Sol 3919 S to eliminate any trace of mold release agents or wax It may require two or three washings Thoroughly abrade the surface to be painted by wet sanding with 180 grit sandpaper followed by 220 grit Follow the paint manufacturer s recommendation for the fi nal grit Gener
178. tions that might cut you You have a couple of options for final finishing 1 Do nothing Since most of the work is in the bilge area you do not need to apply a final fin ish UV degradation of the epoxy will not be a problem and in many circumstances the appear ance of the repair does not matter 2 Paint the repair If the appearance of the repair matters select a paint color that matches the rest of the area and paint the repair Proper surface preparation of the repair includes washing with water and thoroughly sanding the epoxy surface Section 9 4 7 Final surface prepara tion Apply a paint primer or apply the topcoat directly to the prepared epoxy As always when you re installing any hardware use epoxy to seal all holes you drill If you ne glect this step you will likely have another repair job in a few years when the core material rots 3 5 Reinforcing to improve panel stiffness Small cracks and flaws in panels can be a result of high stress concentrations and flexing within a panel A common example of this problem is hairline cracking around the perimeter of a foredeck usually the result of the deck s flexing under load Similarly a lightly built hull may experience considerable flexing as it pounds through waves resulting in cracks around bulk heads In the flatter bow areas panel flexing or oil canning often results in gelcoat crazing Such deflections can be controlled by reinforcing these panels
179. to structural repair on fi berglass boats It covers repairs to cored and non cored panels and how to apply gelcoat over epoxy repairs Gelcoat Blister Repair with West System Brand Epoxy is a guide for repairing and preventing gelcoat blisters on fiberglass boats It includes an analysis of the factors contributing to blister formation and steps for preparation drying repairing and coating for moisture protection Fiberglass Boat Repair amp Maintenance Published by West System Inc P O Box 665 Bay City MI 48707 866 937 8797 www westsystem com 14th Edition 12 06 BRAND
180. u have access to the back of the panel bond a plywood block to the inner side of the panel The block should be thicker than the length of fasteners and cover an area beyond the perimeter of the fasteners The larger the block the greater the load transfer area With the block in place follow the basic fas tener bonding procedure described above Panels without back access If a small fastener hole in a non cored panel is stripped and you don t have access to the back of the panel the hole can be plugged to regain some holding power This technique is not recom 7 mended for high load applications 1 Enlarge the stripped holes to at least 1 4 6mm diameter or about twice the screw diameter 2 Cutacylinder or cube of flexible open cell foam with a cross section about twice the hole diam eter Figure 7 1 Work the foam through the hole with a small stick or nail and allow the epoxy to cure thoroughly Grind the foam flush with the surface and re drill a pi lot hole in the foam Flexible open cell foam 49 Installing Hardware 3 Saturate the foam with epoxy and insert the foam into the hole Work the foam through the hole with a small stick or nail Allow the epoxy to cure thoroughly with most of the foam vol ume on the inside of the hole Figure 7 1 4 Grind the foam flush with the surface and re drill a pilot hole in the foam Wet out the pilot hole thoroughly with epoxy before reinstalling the hardware
181. uate ventilation is not possi ble wear a NIOSH National Institute for Occupational Safety and Health approved respirator with an organic vapor cartridge Provide ventilation and wear a dust mask when sanding epoxy Using WEST SYSTEM Epoxy 62 especially uncured epoxy Breathing uncured epoxy dust increases your risk of sensitization Al though epoxy cures quickly to a sandable solid it may take over two weeks at room tempera ture or post curing to cure completely Avoid ingestion Wash thoroughly after handling epoxy especially before eating or smoking If epoxy is swallowed drink large quantities of water DO NOT induce vomiting Because hard eners are corrosive they can cause additional harm if vomited Call a physician immediately Refer to First Aid procedures on the Material Safety Data Sheet KEEP RESINS HARDENERS FILLERS AND SOLVENTS OUT OF THE REACH OF CHILDREN For additional safety information or data write to EPOXY SAFETY West System Inc P O Box 908 Bay City MI 48707 USA 9 1 1 Cleanup Contain large spills with sand clay or other inert absorbent material Use a scraper to contain small spills and collect as much material as possible Follow up with absorbent towels Uncon taminated resin or hardener may be reclaimed for use DO NOT use saw dust or other fine cel lulose materials to absorb hardeners DO NOT dispose of hardener in trash containing saw dust or other fine cellulose materials spontaneous c
182. upport the fibers in positions to effectively carry and spread the loads Generally the higher the proportion of fiber to resin in a laminate the greater its strength and stiffness The continuity of these resin fiber skins is critical to the integrity of the structure It is often nec essary to cut through the skin while carrying out repairs even though the skin itself may not be damaged Keep in mind that one objective will always be to rebuild for skin continuity to return the load carrying ability of the fibers in the laminate to original or greater strength 1 1 1 Fiberglass resins 1 1 2 Fibers The vast majority of fiberglass boats in use today are built with polyester resin Modern unsatu rated polyesters used in boat construction are made up of three basic components glycol or ganic acid and reactive diluents usually styrene If you were to look at uncured polyester resin at a molecular level you would see what appear to be thousands of chains made up of alternat ing glycol and acid units These chains are polyester pre polymers Adding a peroxide catalyst typically MEKP to the polyester resin mixture initiates a cross linking reaction that causes the styrene to create bridges linking adjacent pre polymer chains together As the mixture cures more and more bridges are established and the free flowing glycol acid chains begin to gel be coming a solid mass Eventually enough bridges are built to form a rigid three dimensiona
183. using WEST SYSTEM epoxy Pan els can be reinforced by adding fiberglass core material and fiberglass or stringers with or with out fiberglass Some of these reinforcing methods can be further improved with the use of graphite fibers 3 5 1 Reinforcing with fabric Perhaps one of the simplest methods of reinforcing a large area particularly the hull is to lami nate layers of fiberglass fabric to the interior surface of the hull or deck to increase the thickness of the laminate Bonding layers of fiberglass fabric to a panel is covered in Section 9 4 5 Ap plying woven cloth amp tape Multiple layers of fabric may be applied one after the other or before the previous layer has become tack free Step each layer back from the previous layer progres sively smaller layers to avoid stress concentrations at the edge of the stiffer area 3 5 2 Reinforcing with fabric and core material As noted in the introduction doubling the thickness of a laminate will increase its stiffness by eight times Bonding a core material between the fiberglass fabric and the interior of a panel is a good way to increase stiffness with a minimum amount of added weight Either end grained balsa or a rigid closed cell foam are good choices for a core material This method of reinforce ment is useful over large areas with good access to the interior side of the panel 17 Repairing Stringers and Floor Stiffen a flexible panel by bonding core material and fibergla
184. ve with one part gelcoat Spray the first coat of this mixture over the previously sprayed area Then apply two or three more coats of this mixture over the entire area Extend each coat farther than the previous one with the last coat out to the tape line The semitransparent film of lightly tinted clear patching additive will allow the original gelcoat color to show through around the perimeter of the patch This will help blend any subtle color change into the original gelcoat 9 Repairing Minor Cracks and Holes 11 12 Allow the gelcoat to reach a full cure Pull the tape and sand the tape line smooth Start with 320 grit wet or dry paper and work up to 600 grit Sand the surface of the repair if necessary Buff the surface with a white medium cut rubbing compound Take your time and do not over heat the surface while buffing The excess heat can cause a stain that will be very difficult to re move Finish with a fine compound and wax the area There are times when the repair will not match simply because the original gelcoat color has faded You may need to polish the entire section of the boat to restore the original color 2 2 2 Paint finishes Although almost any high quality marine grade paint will work we recommend using one of the two part polyurethane paint systems above the waterline Below the waterline apply bot tom paint directly over thoroughly cured WEST SYSTEM epoxy These paints provide ultravio let protec
185. wing at the top to offer less weight If fiberglass fabric is to be applied over the stringer the trapezoid shape allows easier fiberglass fabric application Figure 3 7 The upper edges should be rounded to eliminate sharp corners Figure 3 7 Laminated or solid wooden stringers pro j vide effective panel rein j forcement with or without the addition of fiberglass fabric Install new stringers as described in section 3 4 Apply fiberglass fabric over the stringers as de scribed in section 3 5 Laminated wooden stringers Laminated stringers have structural advantages over cut stringers especially in curved areas Laminated stringers are made of multiple thin layers of wood and can duplicate the shape of the inner side of the panel More of the wood grain in the stringer follows the shape of the panel making laminated frames stronger The new frame can be laminated in a simple jig made from a pattern or in some cases directly in place on the back of the panel When preparing wood for laminated stringers e Use wood strips thin enough to bend easily into the shape of the panel Be sure all of the strips collectively can bend to shape Thick strips want to relax or springback e For a curved frame with greater strength and less springback use more thinner strips for a given stringer thickness e Use full length strips Make the strips longer than the finished stringer to allow for trimming e Select wood strips that are se
186. xy tempera ture above the hardeners minimum recommended application temperature Use a hot air gun heat lamp or other heat source to warm the resin and hardener before mixing or after the epoxy is applied At room temperature supplemental heat is useful when a quicker cure is desired CAUTION Heating epoxy that has not gelled will lower its viscosity allowing the epoxy to run or sag more easily on vertical surfaces In addition heating epoxy applied to a porous substrate soft wood or low density core material may cause the substrate to out gas and form bubbles in the epoxy coating To avoid outgassing wait until the epoxy coating has gelled before warm ing it Never heat mixed epoxy in a liquid state over 120 F 49 C Regardless of what steps are taken to control the cure time thorough planning of the applica tion and assembly will allow you to make maximum use of the epoxy mixture s open time and cure time 9 3 3 Dispensing and mixing Careful measuring of epoxy resin and hardener and thorough mixing are essential for a proper cure Whether the resin hardener mixture is applied as a coating or modified with fillers or ad ditives observing the following procedures will assure a controlled and thorough chemical transition to a high strength epoxy solid Dispense the proper proportions of resin and hardener into a clean plastic metal or wax free paper container Don t use glass or foam containers because of the potential dang
187. you are working with a lead or metal keel wire brush the surface while the epoxy is still wet for a better bond Allow the epoxy to gel Apply a 1 2 wide ridge of epoxy 407 or 410 filler mixture thickened to a stiff peanut butter consistency to the surface at each template location Use a plastic squeegee to trowel on the fairing mixture slightly thicker than the finished profile A squeegee notched to the shape of the ridge is helpful to shape the mixture Cover the ridges with strips of 879 Release Fabric to keep the fairing mixture from sticking to the template Lightly press the release fabric to the ridge Do not press hard enough to flatten the ridge Push the templates into the soft mixture to make an impression of the exact keel profile at each template location To gauge the depth of the impression height of the profile push the tem plate into the mixture until the centerlines marked on the template match the centerlines marked on the leading and trailing edges of the keel Figure 8 6 If an area of the ridge is too low to contact the template when it is properly aligned squeeze the material under the release fabric upward so it comes in contact with the template When you re satisfied carefully remove the template leave the release fabric in place and allow the mixture to cure thoroughly Remove the release fabric and mark the center of the template impression with a permanent felt tipped marker to act as a sanding
188. you choose to use this method we recommend the following procedure Figure 3 2 Inject or pour resin hardener mix ture into the holes when the core is dry and while a k Ji the core is warm 3 6 holes 1 apart Repairing Stringers and Floor 12 1 Drill a pattern of 3 6 diameter holes over the rotted area Space the holes 1 or less from center to center in all directions Drill each hole deep enough to pass through the rot just into solid wood 2 Dry the core thoroughly If necessary use heat guns or fans to accelerate drying 3 Inject or pour resin hardener mixture into the holes while the core is warm Figure3 2 Epoxy warmed by the core will become thinner and penetrate more deeply into the exposed end grain 206 Slow Hardener should penetrate more deeply than 205 Fast Hardener before it be gins to gel 4 Continue to inject epoxy into the holes until the core can no longer absorb epoxy and the voids under the skin are filled 5 Fill remaining surface voids with thickened epoxy after the injected epoxy reaches its initial cure if necessary Use an epoxy low density filler mixture for cosmetic fairing of the surface 6 Apply a layer or two of fiberglass tape or cloth over the stringer to restore stiffness if the damage and hole drilling is extensive 3 2 Stringer repair guidelines For more serious repairs that involve removing and replacing stringer material try to duplicate the original construction

Fibeglass boat and repair maintenance.

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