Mold Making and Repair Page 1

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1 Mold Making and Repair Page 1 Introduction: The Basics of Building Fiberglass Molds The purpose of this document is to give step-by-step recommendations for producing various plugs, molds and masters, and to standardize some of the terms used to determine the differences between a plug, a mold and a master. While these recommendations are not the only way of performing these tasks, the guidelines herein have been proven in pattern and mold shops over many years. A plug is generally comprised of wood or existing fiberglass pieces, clay or hard fillers for the radii, and will be both dimensionally correct and shaped exactly as the finished fiberglass unit would appear. After preparing the surface of the plug for the application of polyester tooling gel coat and layers of fiberglass laminate, a reverse image of the mold is built and removed from this plug. The mold is then prepared for a fiberglass master in the same fashion as the plug was prepared for the mold. The plug produces the mold, and from the mold comes a fiberglass master. This master will then produce molds that will produce finished fiberglass units. Plugs are constructed in the shape of the desired finished product. When a plug requires precise tolerances of dimensional stability or intricate design lines, these are generally shaped or formed by the plug-builder to the satisfaction of a blueprint or an artist's conception of what the finished fiberglass product should look like. As a rule, plug-builders insist that the plug's finished surface have the esthetic appearance of a finished, marketable fiberglass unit. For example, if you were to build a plug for the deck of a boat or a truck cap, you would be utilizing a quality grade of plywood for shaping the flat areas and fillers for the radius areas. You would also make sure that the finish on the completed plug would be as smooth and shiny as the fiberglass part to be produced from the mold made from this plug. Remember: The mold is a mirror image of the plug, and the finished part will reflect the surface of the mold. Concentrating efforts on the plug will enhance every stage thereafter. One of the most successful ways to achieve high gloss, mirror-like finish over wood and other substrates is to use high polyester paint systems, such as Fourseal and Fourgard. For information on Fourseal and Fourgard please contact one of our many customer service centers.

2 Mold Making and Repair Page 2 Building a Plug Procedures and techniques for building plugs will vary from individual to individual and from shop to shop. For simplicity, this document will discuss the building of a truck cap plug. Remember, though, that the plug being discussed for illustrative purposes could just as well be a boat hull, a bath tub fixture, a recreational vehicle part or other parts, including multiple-piece units. Several of the most commonly used materials in plug building are 3/4 inch birch plywood or other high density wood, 2x4 and 2x6 lumber, and a wide variety of fillers for forming radii and detail lines. First we ll cover the use of wood and existing substrates, then we ll discuss other materials - plaster and hemp, foam blocks, and paraffin wax. The two most common layout techniques are flat sections reinforced with lumber and skeleton framing reinforced with exterior emplacements. Skeleton framing is generally used in the construction of large boat hulls or decks. A skeleton is constructed to dimension, and the exterior emplacements are added to the skeleton. The flat, reinforced method is generally used for plugs requiring straight, non-wavy areas. As a finished unit, a truck cap requires an accurate fit to the bed sections of different makes and models of trucks. Therefore, one of the first steps to address is the marriage of the unit to the truck bed section. After building a reinforced, level, stationary platform and after marking the dimensions of the bed of the truck directly on this platform, we can then establish a line of reference to begin our layout work. This procedure lends itself well to making recreational vehicle parts that must fit in rough openings or to boat parts that must fit over existing parts, for example, a deck plug that goes over an existing fiberglass hull section. Now that we have a system of determining what the outside dimensions are to be, we can build our rough layout up to these lines of reference. We are now ready to cut all our straight plywood pieces and to reinforce them with the 2x4 or 2x6 lumber. Use kiln dried lumber and exterior grade plywood. By reinforcing each piece of plywood with lumber placed on edge and not flat, we can hold the surface of the plywood straight and true. The plywood should be cut very precisely with all the edges that are to become radii cut at a bevel. This bevel cut will allow the radius to be formed with a filler that can be worked into shape, which is easier than attempting to form these radii by shaping the plywood itself with sandpaper or files. When attaching the lumber to the plywood, inset all screws or nails into the face of the plywood. When we finish the exterior of the plug, we will fill these fastener holes with filler or wood dowel pins that should be sanded flush. Wood dowel pins are the better selection, as shrinkage will occur with most fillers. In addition to screws or nails, use wood glue to help fasten the lumber to the plywood. After the Plug has been totally assembled, except for the radii and the finish, seal the inside or under side of the wood with polyester resin or another waterresistant material. This will prevent warping due to humidity as we continue to build our Plug. If a male plug is being constructed, the outside of the plug becomes the inside of the mold. Therefore, the gel coat surface will be on the exterior side of the part. This means that if the part needs to fit over another object, we will have to allow for the thickness of the laminate. When the design of the plug requires a split mold, in order to remove the part, the plug should be constructed as a single unit. The split areas can be determined after the rough forming is completed.

3 Mold Making and Repair Page 3 Procedure for Multiple Section Plugs 1. Split the plug in radius areas when it is practical to do so. 2. Cut walls as close to the surface of the plug as possible. 3. Wax the area under the wall. 4. Fill the bottom of the wall with a patching paste. Position it back over the plug, and allow it to cure. 5. Clean the excess patching paste off the plug surface. 6. Save this wall for the lamination process. 7. Use aligning pins or dowels so both sections will join together perfectly. We have determined where we are to split the mold and have constructed a wall that fits exactly to the area of the plug. Now we are now ready to laminate this section only. We will then remove the wall and laminate the other section up to and including this wall which will give us two mold sections, married together, at the walls. We can then bolt or clamp these walls during the manufacture of the parts. Fillers such as modeling clay, body putty or filled polyester and micro balloons are used for shaping and forming radii areas and design lines. Fillers should lend themselves to being sanded and filed easily. This will make the rough forming and finishing of the radii easier. Drags constructed of Plexiglas or wood and shaped into the size and dimensions needed, are excellent ways to form both inside and outside radii. Design lines or multiple radii can be formed in this same manner. Some manufacturers specialize in making intricate drags and radius finders. Finishing the plug is commonly the most important and the most difficult task of the builder. Fortunately, some new products on the market allow a paint-style finish with polyesters. These products are high-build systems, which can be applied in mils with one application, using several passes. Caution must be taken when applying these types of materials. The specific instructions issued by each manufacturer should be followed closely, since this material is different from a polyester gel coat.

4 Mold Making and Repair Page 4 Preparation for Re-Surfacing Step 1: Sand the substrate or the existing surface with 40 to 80 grit sandpaper using an orbital sander or by hand. When resurfacing a mold or part, the surface need not be completely removed to the substrate. It should, however, be free of any glossy areas. Dry sanding is recommended. Step 2: Check for any cracks or chips penetrating through the surface into the substrate. If present, they must be repaired immediately, as any laminate defects will eventually transfer to the surface. Step 3: Repair all surface cracks, chips or gouges with a repair paste. Mix only the amount of repair paste that can be used within minutes. Add 15 drops of MEKP peroxide catalyst to one ounce (30 grams) of repair paste. Mix thoroughly by stirring and folding. Apply with a spatula, putty knife or squeegee. Fill the void completely by working the paste in all directions. To repair large areas with a repair paste, slightly mound the paste to ensure a complete fill after curing. Since this is a polyester material, add a colored gel coat if a color is desired. Large voids may be reinforced by adding milled glass fibers or other similar reinforcement to the paste. Since repair paste shrinks very slightly, the application of heat to the repaired area will insure that all shrinkage has occurred. Use a heat lamp or a hair drier for "post curing" this material. Be careful not to over-heat the area surrounding the patch. Step 4: Wipe the entire surface clean to remove dust or other contaminants. Remember: This procedure is only for repairing the surface of an existing mold that is to be resurfaced. Now we are ready for the primer. High-Build Polyester Primers Step 5: Prepare primer by adding % by weight of MEKP peroxide catalyst and mix thoroughly. Dilute with a recommended solvent at the rate of 10 parts by volume of primer to 1 part by volume of solvent. Prepare only the quantity that can be sprayed within minutes. If longer pot-life is required, slightly increase the portion of solvent. Do not exceed 25% solvent Step 6: Apply a wet first coat (4-6 mils) to the entire surface, allowing the solvent to flash off for 1-2 minutes. Then continue to build up to the desired thickness in 5-mill passes. Do not exceed 30 mils per application. The primer coat will be dry to the touch in minutes. For best results, allow it to cure 6 hours at room temperature at 77 F., at which time it will be ready for sanding. After a one-hour cure at these temperatures, you may accelerate the cure by applying air and or heat. Do not exceed 130 F. Never coat with PVA or other sealants. Air is needed for curing. Step 7: Sand the entire primed surface to the desired finish with grit sandpaper. Remove all orange peel from the primer since it will transfer to the surface after the topcoat has been applied. Because primer sands so easily, do not bear down hard with the sandpaper. The primer may be buffed and prepared for a quick mold. However, to achieve the mirror image the top coat must be applied. Dry sand for best results.

5 Mold Making and Repair Page 5 High-Build Polyester Top Coat Step 8: Wash and wipe the primed surface with a recommended solvent to remove dust and contaminants. Step 9: Prepare the high-build polyester topcoat by adding %, by weight, of MEKP peroxide catalyst and mix thoroughly. Then dilute with a recommended solvent as required. Remember to catalyze only the polyester and not the solvent. Example- 20:1 or 10:1 topcoat to solvent by volume. Mix only the quantity that can be sprayed within minutes. For longer pot-life, increase the portion of solvent slightly as required. Never exceed 50% solvent. Step 10: Spray the entire surface with a wet mist layer (2-3mils) at the lowest air pressure that will allow adequate atomization. Wait 1-2 minutes for the solvents to flash off. Apply the second coat to cover and hide the primer or existing substrate. Wait another 2 minutes and apply the flow coat, which should look wet and glossy. Each of the three layers must look wet. There will be no gloss retention loss from wet to dry. To enhance the cure, use heat and air. Do not exceed 10 mils per application. If higher build is required, allow to cure, then sand and build 10 additional mils. The topcoat will dry to a hard and glossy finish without additional sealants. Dust particles can be easily removed by sanding or buffing slightly. Step 11: Allow 6-8 hours at normal room temperature for curing. The application of mild heat will accelerate the cure. When fully cured, final finishing can be carried out by lightly sanding with grit sandpaper. Wet sanding is recommended unless wood is exposed. Do not sand the sharp radii. Buffing these areas will eliminate the possibility of removing the coating. Placing masking tape over the radii when sanding will protect them adequately.

6 Mold Making and Repair Page 6 Helpful Hints and Important Reminders 1. Be sure that the part being surfaced does not have substrate cracks that have not been repaired. Otherwise surface cracking may occur. 2. For superior adhesion, apply primer to all parts to be surfaced. Do not take shortcuts by applying the topcoat directly to the substrate even if it is in apparently good condition. 3. When spraying, keep the gun far enough away from the surface so that the pressure from the atomizing air fan does not ripple the coating. This will minimize subsequent sanding. Use the lowest possible air pressure while still achieving a good spray pattern. 4. A siphon gun, with a material flow regulator, is recommended. Larger jobs can be sprayed with airless equipment using a paint tip (.013in.) designed for low viscosity materials ( CPS) 5. Spray the coating in work areas where dust is at a minimum. 6. If, during buffing, the surface remains dull, either allow more time for post-curing or expose to heat. Review the entire procedure before repeating it on another application. 7. First, wipe down the mold surface with a solvent. 8. Use a recommended solvent to dilute either polyester primer or topcoat. 9. The purpose of adding the solvent is to increase the pot-life as well as to reduce the viscosity. Do not attempt to use this type of system at or below 50 F. 10. Most unsaturated polyesters are not recommended for total immersion in water or other liquids.

7 Mold Making and Repair Page 7 Catalyst Chart The following charts give the quantity of MEKP peroxide catalyst in cubic centimeters to be used with either a gallon or quart of polyester coatings. All catalyzation of polyesters is based on weight, not volume. These charts are very close approximations of the conversion of weight to volume, that is, of grams to milliliters. Most polyester products have the weight per gallon on the containers. Good guidelines for gel coat weight per gallon are as follows: Under-catalyzing will severely affect the quality of the final product, and over-catalyzing will create production difficulties and waste money unnecessarily. As the chart indicates, different coatings do require different levels of catalyst to maintain the proper percentage. Please use these as guidelines for better parts. Whites Black & Other Clear 11 pounds per gallon 10 pounds per gallon 9 pounds per gallon One Quart Wt./gal 2.0% 2.5% 3.0% 3.5% 11 lbs. 25cc 31cc 37cc 44cc 10.5 lbs. 24cc 30cc 36cc 42cc 10 lbs. 23cc 28cc 34cc 40cc 9.5 lbs. 22cc 27cc 32cc 38cc One Gallon Wt./gal 1.5% 2.0% 2.5% 3.0% 11 lbs. 75cc 100cc 125cc 150cc 10.5 lbs. 71cc 95cc 119cc 143cc 10 lbs. 68cc 91cc 113cc 136cc 9.5 lbs. 65cc 86cc 108cc 129cc

8 Mold Making and Repair Page 8 Plug Building with Other Materials The following list cites other materials that can be used when constructing plugs designed for specific applications, as well as units that have been produced with these various materials.!. Plaster & Hemp: Plaster and hemp (rope) material can be mixed to form a pourable concoction. The plaster is reinforced by the hemp material. This process works well when a quick splash is required in establishing rough design or rough dimensions in the least amount of time. It can be applied eight to ten inches thick in one application. For instance, to determine the rough dimensions of a wheel well on a truck or the curvature of the side wall of a truck, this plug template would be both quick and inexpensive. The surface of the plaster will remain pitted and porous but will exhibit dimensional stability. For a quick mold, we could build the first three layers of laminate over the plug as though we were building a mold and then back up the laminate with this concoction. This would allow a "one-off" temporary glass mold. 2. Foam Blocks: This is usually a low-density foam carved to a specific shape, with consideration being given more to shape than to dimension. One use might be the forming of a statue or a logo that requires a large degree of artistic design and self-expression. To produce a mold from a foam plug, apply a coating after the design has been established. This coating could also be polyester resin and a fiberglass, laminate or polyester primer. Usually this kind of plug will be good for making one reproduction only. Higher density foam used in this manner will produce several reproductions. Such high-density, carved foam, is often used to create intricately "carved" furniture reproduced in foams or polyesters by means of a room temperature vulcanized rubber (R.T.V.) mold. The parts are produced from the same low or high-density foam materials as are the plugs. Regardless of the density of foam being used, the procedure is as follows: a. Carve and shape the foam into the desired configuration. b. Apply a release agent to this surface. (512B PVA) c. Pour the R.T.V. over this carving. d. Allow the R.T.V. to cure. e. Remove the R.T.V. from the carving. f. Apply a release agent to the R.T.V. reproduction. g. Pour the low or high-density foam into the R.T.V. mold, reproducing the original carving. h. De-mold the carving, which will match the original carving used as a plug. Church furniture, novelty plaques and automotive prototype units are a few additional applications for low and high-density foam products. 3. Paraffin Wax: Paraffin is generally used to produce fiberglass musical instruments such as horns or parts that will be produced only once from each mold. The process is unique, since virtually any twisting curvature can be produced with this system. After shaping the paraffin wax, apply a laminate to the exterior side of the shape. When the laminate has cured, insert a hot wire into the paraffin and the paraffin plug will melt away from the laminate. Obviously, this procedure has limited uses and requires the rebuilding of a new paraffin tool after each part. However, the paraffin is reusable.

9 Mold Making and Repair Page 9 Preparing the Plug for a Mold When the plug is finished and approved, it must be prepared so that the mold will release from the surface of the plug. Many release agents, compounds and procedures in today's market work well in the fiberglass industry. Therefore, this document will suggest a method of selecting the system itself. Due to the complexity of specialized release agents used with a wide variety of techniques when addressing plugs that are comprised of sophisticated materials, we will focus on plugs that have been surfaced with polyester-type materials or with materials that are compatible with polyesters. The four basics of preparation are: 1. Sanding 2. Compounding 3. Sealer Glaze 4. Waxing / Release Agent 1. Sand the surface with the finest grit of sandpaper possible. The larger the number on the sandpaper the finer the grit. Example: (a) 1200 Super fine grit (b) 600 Finer grit (c) 400 Fine grit (d) 320 Medium grit (e) 220 Medium grit(f) 180 Course grit (g) 80 Rough grit These number ratings are generally printed on the backside of the sandpaper. The two types of sandpaper are wet and dry and dry open grit. When sanding is required on a wood plug, use dry, open grit sandpaper in order to eliminate the possibility of swelling any exposed wood areas with water. If the plug is totally encapsulated, wet sanding is possible. In fact, it is better, since it will cut faster and limit the amount of work required. Always block sand with a flat sanding block, unless the design of the plug does not allow you to do so. Sand with 400 grit, follow that with 600 grit, then finish with 1200 grit. Next, sand the 400 in one direction, then the 600 in the opposite direction, followed with the 1200 in the same direction as the 400. This would sand the coating down in a uniform manner and end with all scratches left by the 1200 grit going in one direction. The straight scratches would then be removed by the circular motion of the buffing pad that would cross over the scratches left by the 1200 sandpaper. 2. Compounding with materials made by the same manufacturer seems to be one of the most overlooked procedures when selecting a compound. There are thousands of buffing compounds on the market today. Some are formulated exclusively for paints, metals, plastics or polyesters. Using products made by the same manufacturer guarantees that when heavy-duty compounds and lighter grit compounds are used they will be compatible in chemistry and will not have an adverse reaction with each other. Most buffing pads are 7-inch, curved-edge 100% wool material. Synthetic materials can leave a residue that can cause a breakdown of the waxes to be applied later. Buffing pads should not be laundered with industrial soaps. These can contaminate the surface, leaving a residue that is released on the unit when the pad becomes warm during the buffing process. In buffing, the pad is placed on the curved edge of the pad and pressure is applied to the compound via the pad. Polishing the streaks left by the buffing action is accomplished by laying the pad flat and applying very little pressure. During this process, keep the buffing pad clean and free of grit while moving the buffer briskly over the surface. After the buffing process has been completed with heavy duty compounds, regular compounds and finefinish compounds, the entire area that was compounded should be wiped clean with warm clear water and dried. This will remove any existing compounds and will prepare the surface for the sealer glaze. 3. Sealer Glaze seals the microscopic pores (not porosity) in the surface of the gel coat, (which were

10 Mold Making and Repair Page 10 Preparing the Plug for a Mold (Continued) opened by sanding) and leaves a glaze on the surface in preparation for the wax. Sealer Glaze should be applied with a machine buffer using the polishing technique of laying the pad flat and applying little pressure. Always use a clean pad that has not previously been used for buffing compounds. This will prevent the possibility of applying compound back to the surface that you had previously washed with clean, warm water. Again, for chemical compatibility, the sealer glaze material should be from the same manufacturer as the buffing compounds. 4. Waxing the plug accurately and with an adequate amount of wax will assure the releasing of the plug from the mold. Failure in this procedure can result in the entire loss of both the plug and mold. The following procedures for waxing are considered basic guidelines: a. Start the waxing in one specific area and stop at the same area. This should guarantee coverage of every inch of the plug's surface. When you start and stop in different places, you can forget where you have been with the wax. b. Make small circular motions when applying wax. Let them overlap each other, being cautious not to apply heavy concentrations. Heavy concentrations of wax will not release the solvent and will smear when you try to remove the wax. c. Allow the wax to become hazy, but not completely dry before wiping the wax from the mold. If you apply wax, remove it and apply a layer immediately on top of this green, non-cured layer, you accomplish nothing. After you remove the layer of wax, allow time for the solvents in the wax to be released. Usually 30 to 60 minutes is adequate. d. For wiping materials, use a lint-free, undyed, uncontaminated, clean material. If you use this A-B-C-D-system of wiping off waxes, you should end up with a clean piece of wiping material when you have finished. Depending on the size of the plug, start with the number one rag in one hand and the number two in the other. With the same circular motions used when applying the wax, wipe the wax off. Use the number three and number four rags in the same manner. After the wax has dried for several minutes, wipe the entire unit one more time with a clean rag. Allow each layer to cure for minutes prior to the next layer. 4. Every builder has his own theory concerning how much wax is enough. If it's not broke, don't fix it! If you have problems, usually 7 coats spread over a 2- day period seems to work well. Thus far, we have built a sound foundation, formed our shape to dimensions, made radii and design lines using drags, sealed the under side, applied a primer, sanded, applied a mirror finish, sanded lightly, buffed, seal-glazed and waxed the plug. We are now ready to build a mold, or the reverse image of the plug. Remember: Any flaw in the plug, regardless of how minor it may seem, will transfer to the mold surface. Prior to making a mold the plug must be perfect!!

11 Mold Making and Repair Page 11 Building a Fiberglass Mold A few basic rules can make building a mold into a science. One of the most important rules is to document all of the materials, dates, batch numbers, quantities of materials used and temperatures. Regimenting yourself to weigh chemicals accurately and consistently will give you a good point of reference to troubleshoot any problems that might occur with a particular mold. When a problem occurs, change one item at a time until you find a solution. For example, if cure is a problem, change the catalyst. If the problem still exists, go back to the original catalyst and change the resin. If the problem goes away, it had to be the resin. If you make several changes at the same time and the problem disappears, you will not be able to determine the cause. Equipment plays a leading role in producing a good mold, therefore, keep all equipment -both spray and manual tools- in clean working order and regiment yourself to accept nothing less. STEPS IN BUILDING A MOLD There are 6 major steps involved in building a mold. Each individual segment should be documented and kept on file for future reference. This information can be compiled and placed on one simplified document. (See "Mold Birth Certificate"). These steps are: 1. Material selection and Q.C. 2. Equipment 3. Gel Coat Application 4. Lamination 5. Bracing/Bridging 6. Documentation Material selection, quality control and application are the most crucial steps when building a mold. Of course, the gel coat should be manufactured as a tooling product. General characteristics of a tooling gel coat: 1. Has a slow gel time (20-30 minutes) and a fast gel to peak (20-30 minutes). The times are film-cure times. Add these together and multiply times 3 for the lamination time of minutes. 2. Creates a peak temperature of no less than 360 F. and no more than 450 F. These temperature ranges should create a cure cycle that will generally assure a harder surface. 3. Releases air in minutes at 20 mils wet in order to assure a porosity-free layer of coating after cure. 4. A Hegmen grind of is a desirable reading. This means that the largest particle sizes found within the material itself would be 1-1/2 mill in size. 5. One of the final steps prior to applying the tooling gel coat is to spray a test panel with the same catalyst levels and mils that you will apply on the master. Check the panel for air release (porosity) by sanding the test panel. Also check for cure, spraying and any other visual defects, etc. Porosity is small entrapments of air. When the coating enters the gelation stage, prior to the air completely exiting the coating, you will see small pits on the surface or directly below the surface as you sand. The most common causes of porosity are too fast of a gelation cycle (lower catalyst levels to allow more air release time) and dry spraying the material during application of each layer (apply each layer wet). Pour a small sample of this mixture into a metal can lid. The gel coat can be removed from the lid cast after 2 hours. A barcol of should be established at this time. After hours, a barcol of suggests that a hard and therefore high-gloss finish will be likely. Barcol hardness is tested by an impresser and by measuring the resistance to impression. Gel coats will read from Glass laminates will have a hardness of 60+. Having systematically selected your tooling gel coat and authenticated the properties by our Quality Control methods, you are ready to organize the gel coat booth and apply the tooling gel coat.

12 Mold Making and Repair Page 12 Organizing the Gel Coat Booth Organizational methods within the gel coat booth should become a part of the assigned procedures for gel coating the mold. If the part is large, two people should be assigned to actually apply the gel coat, since one will become fatigued near the end of the task. One person should mix the coating and inspect the unit for possible thin areas when the gel coaters are finished. The one who mixes should have a catalyst chart posted in the booth and should document the amount of catalyst added to the gel coat and the amount of gel coat applied to the mold. Always record the actual amount of materials added together and not what should have been added. The following mathematical calculation can be used in determining the percent of catalyst after the mixing has been completed. 1. Multiply 454 times the total pounds of material. (gel coat or resin). 2. Divide this total figure by the amount of catalyst added (The larger number will be divided into the smaller number). 3. Divide this figure by This total will be the percent of catalyst added to the material.

13 Mold Making and Repair Page 13 Gel Coat Applications Gel coat applications should be done under careful, well-planned procedures. Listed below are a few standard rules to follow when you apply a pigmented coating. 1. When waxing, start gel coating the mold in the same general area for each pass and stop in the same place. This will keep you from losing your place as you progress around the unit. 2. Apply the gel coat in wet passes, about 5-7 mils per pass. This will allow the coating to release air and will assure a porosity-free surface. If dry passes are applied, the gel coat will air-dry instantly, will not release air and could cause "alligators". 3. The total millage should end at no more than 25 mils wet. Coatings will shrink at different rates but should leave a final layer of about mils dry. Heavier builds could result in cracking and crazing of the gel coat as the mold becomes hot in production. Four wet passes of 5-7 mils should yield the final required millage. 4. The spray gun should be held inches away from the surface of the unit. 5. By spraying perpendicular to the surface and moving the gun in a cross pattern, you will maintain an even layer of coating over the entire surface. Prerelease occurs when the coating shrinks at unequal levels. This can be aggravated by heavy and light layers of coating. 6. Clear tooling gel coat is a process used more and more in today's tool shops. Being able to visually inspect the first mils of gel coat prior to applying the back-up gel coat and laminate is reason enough to consider this process. After applying mils of clear tooling gel coat, inspect the work. Then apply the desired color of the mold on the back side of the clear at about 7-10 mils. If you find air entrapment, dirt or any other defect in the clear, remove it from the mold and take a corrective measure, such as lowering the catalyst levels, etc. Some benefits of clear tooling: 1. Higher gloss retention due to the higher resin solids in the clear. 2. Easier releases due to a tighter surface created by the lack of fillers such as pigments. 3. Non-noticeable repairs. Most pigmented systems become noticeable, even when the same batch and product are used, due to the difficulty in matching the cure times, cover and hide of the unit being repaired. Clear is clear. There are no cover and hide problems associated with clear. 4. Clear can be applied with a hydraulic, "airless" piece of equipment. A pigmented tooling gel coat should only be applied with an "air aspirated" piece of equipment and never with an airless one, due to the high degree of air impregnated into the coating by hydraulic atomization. 5. Less severe wax build-up. There will be fewer such problems than on a pigmented surface because of the fewer wax cycles required for the mold. Two minor problems are associated with clear tooling gel coat: 1. When applying the coating, it is very difficult to visually determine how much coating is being applied to the unit. By making several passes with the gun on a test panel and milling it, you can establish the amount of material being applied per pass. Keep your passes as rhythmic as possible and count your passes. Set the equipment at a level that will give you 5-7 mils per pass at your speed. 2. If sanding is necessary, use a rubber squeegee to wipe the surface being sanded. This will dry the surface instantly, thus allowing you to see how deep you are sanding. The larger and, consequently, the more expensive the mold is to build, the more valuable clear tooling gel coat becomes to the tool-builder.

14 Mold Making and Repair Page 14 Mold Lamination Experts in polyester report that most defects on the gel coat surface of a mold - such as blemishes, glass transfer, dull spots or haziness are the result of a failure in the laminate. If the resin has been undercatalyzed, post-curing will take place as the surface of the mold is heated during production. Post cure will create a hazy, blemished surface as the laminate attempts to cure under heated conditions. Orange Peel can become a factor if the laminate shrinks during the curing process and moves the gelcoat. Guidelines for laminating a good, solid mold: 1. Know the recommended catalyst levels of the resin as issued by the resin manufacturer. 2. Measure precisely the mixing of resin and catalyst. 3. Keep the glass to resin ratio as close as possible to 70% resin and 30% glass. When applying a hand laminate, use a "felt roller" to wet the glass out in order to keep the laminate within the proper ratios. 4. Do not allow the resin to puddle. Because these areas will release heat at different rates, all puddles will eventually transfer to the surface of the mold, regardless of where the concentration of resin is in the laminate schedule. 5. Allow each layer of laminate to dry and cool prior to applying the next layer of laminate. 6. Take barcol readings after each layer and look for at least a after cool down. 7. Document any corrective measures taken on the "mold birth certificate". 8. Use the same catalyst levels throughout the laminate schedule, including the glass covering the bracing. 9. Never use a diluted version of catalyst with the lamination resin. 10. When using core materials, make certain the temperature of the laminate is cold to the touch to avoid any transfer of the core material. 11. Lightly sand between each layer of laminate. This will enhance the mechanical adhesion of the laminate. Remember that the laminate should be compatible with the gel coat. Both should move or flex at the same rate. If the gel coat is harder than the laminate or the laminate is harder than the gel coat, a failure will occur and will normally appear on the gel coated surface of the mold. When the lamination process is completed, the backside of the mold should not have a shiny appearance, indicating too much resin. This should be true for the glass covering the bracing. Make the laminate as neat as possible. BRIDGING OR BRACING THE MOLD Brace a mold with wood, steel, paper tubes or fiberglass. Regardless of the type of bracing, the purpose of the bracing is to support the mold during production as the tool becomes heated and pliable. 1. Never allow the bracing to touch the back side of the laminate. Generally, if the bracing touches it will transfer to the gel coated surface. 2. Place the bracing in a way that maximizes the strength of the material. If 2x4 or 2x6 is being used, turn the lumber on edge for strength. 3. Areas that have radii should not require bracing. A radius exhibits strength by design. 4. When laminating the bracing to the mold, use the same catalyst levels used throughout the laminate schedule. 5. When steel or metal bracing is required, remove any oils or contaminates from the surface. 6. Laminate the bracing as neatly as the mold.

15 Mold Making and Repair Page 15 Removing the Mold From the Plug Three commonly used methods for de-molding: 1. Place wedges between the flange of the plug and the flange of the mold. Make them of wood or plastic to remove the possibilities of scratching the units. Apply pressure evenly by driving the wedges in at an equal distance around the units. Take extreme caution to assure that the wedge does not penetrate the layers of the laminate. 2. Inject air between the plug and mold. The air should be moisture-free and regulated at psi. A common practice is to start a wedge and blow air in the opening created by the wedge. 3. Use water in extreme circumstances where wedges and air cannot remove the units. Since water creates a lot of pressure, take care that the mold or plug does not blow apart due to the pressure exerted by the water. Water and wedges will work well together if the units are difficult to de-mold. After de-molding, examine both the plug and mold for surface defects. If you have been careful when surfacing the plug, the mold surface should be nearly perfect, requiring a minimal amount of attention. When a mold has "flange areas", they should be treated as though they are a part of the mold. This will enhance the life of the mold dramatically. Preparing The Prototype Part Buff, sealer glaze, and wax. Remember to use the A-B-C-D-system of waxing as described previously in the waxing section. The prototype will check for dimensional and esthetic compliance. This check is most critical because the glass master will be produced from this mold. Check all areas of this prototype. Building the Glass Master A glass master will reproduce molds that need little or no work to the surface. The object is to de-mold from the glass master a mold that requires no sanding to the surface whatsoever. A glass master is not required where one or two molds are needed. If the condition of the plug remains stable during the producing of the first mold, continue to build molds from this plug. Check for stability of the plug after each mold is produced. Use the procedures for tooling gelcoat. Build the master as you would a lightly laminated mold. Make the surface of the master as perfect as possible to enhance every mold produced off the master.

16 Mold Making and Repair Page 16 Mold Birth Certificate Gelcoat Date & Time: Type & Color: Gallons Loaded: Gallons Applied: Cat & Type: Cat. Amount: Fld. Psi.: Air Psi: Applied by: Comments: Lamination Date & Time: Layer Position: Side to Side Type & Wt. Class: Front to Rear Resin: gal Cat. c/c Applied by: Inspected by: Comments: Date & Time: Layer Position: Side to Side Type & Wt. Class: Front to Rear Resin: gal Cat. c/c Applied by: Inspected by: Comments: Bracing Date & Time: Glassed by: Pulled by: Type: Inspected by: Comments:

17 Mold Making and Repair Page 17 Mold Repair: Using Putty or Patching Paste The following are recommended procedures for puttying or patching fiberglass: 1. Before grinding out a void to be puttied, wax the surrounding area to enable the excess putty to be removed easily with a putty knife. This will reduce the sanding process. 3. Overfill the patch to compensate for shrinkage during the curing process. 4. Curing overnight is preferable, but if time is a factor, use a heat gun or heat lamp to speed up the curing process. Care should be taken when using this procedure. Overheating will burn the patched area and surrounding gelcoat. 2. After completely burring out the gelcoat in a feathering motion, clean the area free from dirt, oil or contamination. Oils from your hands can cause the patch to fall out or create a dark ring around the patch. 5. Covering the patch with wax paper or P.V.A. will also speed up the curing process. 6. Ambient temperature should be no lower than 70 F.

18 Mold Making and Repair Page 18 Mold Repair: Repairing Punctures The following are recommended procedures when repairing punctures that penetrate into the laminate: Equipment needed: A power grinder with 16 grit disc, cardboard for mixing, solvent, fiberglass material, catalyst, resin, brush, roller, marine grade bonding putty, orbital sander with 80, 120 and 320 grit sanding paper, powered drill and driver, stainless steel screws, safety glasses, mask and gloves. The problem with patching a puncture is joining of the old material and new material. Therefore, it is very important to follow proper procedures. 1. Remove the damaged fiberglass material from the defective area using a power grinder and a 16 grit disc. Feather the area away from the center of the puncture. Grind deep enough to remove all defects. 2. After grinding wipe the area clean with a rag and solvent, removing all dust and contaminates. 3. Use as many plies of reinforcement as equal to the original laminate. Cut the fiberglass to the shape of the hole. Cut the pieces to get progressively larger. 4. The first layer should extend to the outer perimeter of the ground area. All succeeding layers should end with the smallest material in the center of the repair. Work out all air bubbles with a roller or brush. Both the front and back sides of the area should be laminated with fiberglass material. In critical areas where loads are high, the following procedure is recommended. 1. Make the repair as discussed above. After half the material is applied, use a battery powered drill and drill holes through the wet laminate into the old laminate at even intervals. Using a battery-powered driver, drive in stainless steel screws, insetting the screw heads. Continue the material build up. Work the mat and woven roving around the heads of the screws. Let the repair cure. 2. Remove the excess fiberglass and restore the original contour to the area with an orbital sander and an 80 grit disc. 3. Apply a marine grade putty or resin-based milled fiber putty. Catalyze the putty and mix thoroughly so no uncured spots will occur in the patch. 4. Use a squeegee at an angle to flair-out the putty and fill in any indentations in the patched area. Allow the putty to cure. 5. Remove the excess putty. Contour the area by sanding with grit sandpaper. If the initial sanding is done with an orbital sander, sand the putty down until it is not quite equal, with the surrounding area. Finish the sanding process with a sanding block to restore the surface to its original contour. The sanding block should exceed the width of the repair. 6. If dips or pin holes appear after sanding, re-putty, cure and sand again. Use a straight edge to check for a straight, contour before re-gelling.

19 Mold Making and Repair Page 19 Mold Repair: Re-spraying the Gel Coat The following are recommended procedures for respraying: 1. The objective is to re-spray and sand thoroughly, leaving no shiny spots. 2. Sand the area with 220 grit sandpaper using a block or an orbital sander. Do not sand with your fingers. This will cause distortion in the surface, creating dips or groves. 3. Sand the area twice the size of the area to be resprayed. 4. Clean the surface using a solvent and a clean rag. All contaminates left on the surface will affect the adhesion of gel coat. 5. Tape off the area to be worked-on where possible on a sharp break or contour adjacent to the area - even if this means expanding the area slightly in size. This minimizes any slight color or texture differences after spraying. 6. Areas that may possibly be exposed to overspray should be covered. Mark the adjoining area to indicate where the actual spray spot is. This will make it easier to keep track of where you should concentrate your millage. 7. Use gel coat from the same batch the part was sprayed with. 8. Catalyze the gel coat with 2% catalyst by weight. Gel coat can be thinned with Styrene. Do not use more than 5% Styrene or your cure may be inhibited. 9. Stir the mixture thoroughly. It is advisable to use a metal putty knife for stirring the gel coat mixture. A wood stirrer will absorb the catalyst and affect the catalyst percent. 10. Use a siphon spray gun. Test the gun on a panel to adjust the spray pattern. The smaller the area to be sprayed, the more the air pattern and fluid flow should be closed. Air pressure should be at approximately lbs. 11. Position the lighting so you can see the spray pattern as it forms on the surface. 12. Spray the patch area uniformly. Avoid producing runs. Move in horizontal and vertical passes while spraying. Allow proper flow to minimize orange peel. Produce a sufficient build up of gel coat for sanding and buffing. Lower the millage output toward the ends of the sanded area to form a feathering effect. Do not spray outside the sanded area. 13. Clean your equipment immediately after the spraying. Flush with clean solvent. Fill the container with solvent, spraying the solvent through the gun. Back flush the siphon tube by blocking the nozzle of the gun to force solvents in and out of the tube. 14. Allow the gel coat to cure overnight.

20 Mold Making and Repair Page 20 Mold Repair: Sanding The following are recommended procedures for sanding: 1. When using an orbital sander, place the sander flat against the part then start the sander. Starting the sander first then bringing it to the part can cause dips and gouges. 2. Finish sanding with a sanding block. Hold your block flat and apply the sanding block in a continuous vertical and horizontal pattern across the repaired area. 4. Never "finger" sand. This will cause a distortion in the surface. 5. If you have a puttied area on a sharp radius, take down the initial putty with a file. File the putty down until it is almost level with the surrounding area, without hitting the surrounding area. 6. Finish sanding with a block to restore the area to its original shape. 7. Wet sand the area. Use clean water. This will eliminate any scratches caused by particles under the sandpaper. Keep the sandpaper and surface wet. 8. Use courser grits of sandpaper first, then proceed to finer grits, until all scratches are removed and the surface has regained its gloss. 9. Sand with 180, then 320 grit sandpaper. 10. Wet sand with 400 grit sandpaper to remove the 320 grit scratches. 11. Wet sand with 600 grit sandpaper to take out the 400 grit scratches. 12. Wet sand with 1000 grit sandpaper as your final step before buffing. Sanding with 1000 grit will bring the shine back to the part.