My understanding is that gelcoat is what is applied to the mould and on which subsequent layers or glass and resin are built up. We have more than four decades of experience in composite construction in the marine, aviation and industrial applications and are available to answer any questions about our products . . Gelcoat resin usually requires 1 to 2 percent of hardener by volume (follow the manufacturer's instructions). Gelcoat is sprayed into a mold before the glass fabric and resin are applied to provide a smooth pre-finished surface when the part is removed from the mold. 1. the epoxy resin gelcoats are difficult for me to post finish and get a good shine. Also tried a little heat. Then flat sand and spray out (and feather out) the gel using a Preval aerosol spray gun, etc. The most common gelcoats are thermosetting polymers based on epoxy or unsaturated polyester resin chemistry. Do not apply gelcoat to any paint or protective coating because it . - Polyester Type - Epoxy Type - Vinyl Ester Type - Other Type Application Insights This report has provided the market size (sales and revenue data) by application, during the historical period (2017-2022) and forecast period (2023-2028). Question 1: Gelcoat is used as a top-coat, epoxy is used as a structural material (as one part of a composite structure of reinforcing fibers and resin or as a putty) and a bonding adhesive. Gelcoat: Pros: easier to apply (less steps), harder to scratch down to glass, easier to repair a chip/scratch. its also a protectant against the glass fibers as they are not water resistant. Yes gel coat is the most durable and yes you can spray it through a regular gun, but after it cures you have to wet sand and buff it to gloss. Next video will show the results of the tests! Gelcoat and Flowcoat. +. This formula is also resistant to water blistering from frequent use. The primers however are great since they will stick to the polyester and make a great "conversion" coating for your top coating. Gelcoats are modified resins which are applied to moulds in the liquid state. What Is Gelcoat? Use of cheap polyester fillers over which gelcoat will not adhere is a . Thicker coats may be used below the waterline for blister prevention, but the thicker the gelcoat layer, the more prone it may be to stress cracks. WARNING: Prop 65 Notice. Keeping the surface sealed with wax and carefully removing any oxidation on the surface helps prolong its life but eventually they all break down. For top coating with gelcoat you will need to use Duratec High Gloss additive or Surface Agent to get a tack free cure. Both will bond really well. the mixing generates too much heat and the gel kicks too quick. Generically these include epoxies, polyurethane, and both polyester and vinyl ester. Part 1 Preparation 1 Fill in any cracks or gouges in the fiberglass with polyester filler, marine grade. I wouldn't even use an automotive poly based filler on a car, let alone a boat. Sold by Fiberglass Supply Depot and ships from Amazon Fulfillment. This parting film is particularly recommended as a parting agent for separation between polyester or epoxy resins and various mold surfaces. However i thought it was pretty well known that you CAN use gel-coat ontop of west system and have a good bond. Cons: more ongoing maintenance (polishing/waxing), can look chalky, prone to chips. . While epoxy adheres tenaciously to cured polyester, the reverse is not true, so the bond between an epoxy repair and an overcoat of polyester gelcoat will not be strong. Also a good single stage Acrylic urethane is works well too. Gel coat is not as hard and scratches much easier, but is easy to fix. . It is not often used as a post-production finish coating, but it can be applied . Messages. Lighter areas of the hull were unaffected. Trial Unit: 2.31 lbs. Cost can be the second consideration. ft. using MEK as the solvent/thinner for the Gelcoat, and then an overspray with polyvinyl alcohol (PVA or 'parting fluid') to speed the cure .. followed by flat sanding successively down to 800 grit, followed by power buffing. Step 5: Finish the Gelcoat. Fasco Resin Pigments are popular, non-fading, coloring agents for polyester resins, epoxy resins, gel paste, polyester fillers / putties Colors may be mixed to match shades If you desire to tint the gel coat with our coloring agents, mix the coloring agent into the gel coat prior to catalyzing the material The coloring agent can be added at a maximum amount of 1 oz. the job is relatively straightforwardclean and prepare the surface, apply an epoxy primer, sand the primer, remove the sanding residue and then . . Follow by wiping the surface with a clean, dry, lint- free cotton rag. That made it very hard to sand and even coating again. The reason gel coat doesn't stick well to epoxy is not the epoxy per se - it the amine "blush" that occurs on the epoxy surface when it cures - especially when the air is humid. Gelcoat Adhesion Test. After allowing the gelcoat to cure completely, you can then sand and buff your newly gel-coated surface. - Polyester Type - Epoxy Type - Vinyl Ester Type - Other Type Segment by Application - Marine - Wind Energy - Transportation & Vehicle - Fiberglass Pools - Sanitary Ware . There are also Epoxy paints that are very durable too. +. Gelcoat or 'Gel Coat' is a material used to provide a high-quality finish on the visible surface of a fibre-reinforced composite. $14.99 ($3.75/Ounce) In Stock. Gel coat is a polyester resin and uses MEKP as the catalyst. Nov 7, 2014; 142 43: 5 Gallon Unit: per square inch, while a polyester resin can hold less than 500 lbs. remember gelcoat design is to be sprayed into a mold and is designed as a mold release . Correct me if I am wrong. I have tried using duratec (50%) and then spraying PVA over it. The 2 part linear polyurethanes for top coating are the best if you want to paint. Figure 1. $$$ - Gelcoats formulated with polyester resin are much less expensive than epoxy. By far the most common are the two-part polyurethanes, as they provide the ultimate in film integrity and durability. S. I'm pretty sure the information that gelcoat vs. epoxy is a "bad idea" originates from a misinterpretation of what happens . Epoxy bonds to original polyester and vinylester hulls much better than the polyester/vinylester resins. Polyester is more fragile and useful for temporary . . You just have to properly prep the surface before applying the gel coat. Shop. Yes epoxy is better as a barrier but that thin layer of polyester is better than nothing. It is not recommended for use with resins containing water or giving off water during cure (i.e., phenolics) or with automotive finishes, as damage may occur. Gelcoat in the context of boats will always be associated with the high-quality finishes it imparts. 13 Jul 2002. Gelcoat is a resin system that is filled with colorants and thickening agents and applied to a mold surface to form the cosmetic and weathering coating of a composite part. TAP gel coat is a high-performance thixotropic resin that can be used for touch-ups or any top-coat application. If, however, you are making an epoxy part, gel coat is not recommended. Does fiberglass stick to gel coat? per square inch. See all reviews. Start by wet sanding with the finest grit to avoid adding any unnecessary sanding scratches. Polyester gelcoat is a pigmented version of the resin used to build fiberglass boats and other products. Gel coat is typically sprayed in a mold and the structural laminate, or cast polymer matrix, applied behind the gel . On the backside of the gel coat (any polyester) there will be layer of uncured material due air inhibition, this uncured layer is a barrier for an epoxy to get a good bond. Our test clearly demonstrates that polyester gelcoat will bond to a properly prepared WEST SYSTEM epoxy as well as to a cured polyester laminate. About ChromaGlast TM Premium Paint for Composites Use #122-A Gel Coat Thickness Gauge to ensure proper thickness is achieved. Air inhibited gel/polyester has a wax that comes to the the surface and prevents air from contacting the gel which accelerates the curing. They are polyester based and absorb water like a sponge. This might not sound very different to a regular gel . how to gel coat a boat, gel coat restoration near . Get it as soon as Friday, Aug 26. You can use epoxy under gel coat. Allow the surface to dry and sand the surface smooth with 80-grit sandpaper. Once you have the color figured out, comes whether you want to brush the gelcoat or spray it, as we have the . Anything that significantly scratches the gelcoat will also scratch the epoxy. Wash away amine blush with water and an abrasive pad such as a 3M #7447 Hand Pad. Save. Use polyester for repairs that will be gelcoated. . I think you will be fine with either method. Here's 2 video of a test performed by boatwork about the adhesion of polyester gelcoat to epoxy resin. One part polyurethane paints are very shiny and durable, nearly as durable as gelcoat, but much better finish. Far stronger bond! We also found that polyester resin was harder to use the epoxy. These are good general rules when working with composites; either polyester or epoxy. If you feel that you absolutely need to have a gelcoat finish over the repair, then use vinylester resin which is a close second to epoxy but which will accept gelcoat. i would and this is a opinion, do repairs and spray your duratec and get it ready to spray. . They can be rolled on or sprayed. so when sprayed it can be difficult to get it to smooth out. Some people have complained of the toxic fumes from polyester as far away as mile from the swimming pools being resurfaced in their neighborhood. Gel coat is basically pigmented resin you thin down with Acetone to spray.. Spraying gel coat is recommended for more accurate and consistent coverage. Gelcoat derives its name due to it high viscosity and ability to be applied thickly on vertical and overhead surfaces in one coat. Depending on the surface condition it would get blocked with P80 than P120 and reapply the poly, or P120, P180 and D/A with P220 and 2K. Apply gel coat to mold surface. GelCoat cures hard with a self-leveling finish, even on vertical surfaces. 2. Before coating a fully cured layer of epoxy with polyester gelcoat, prepare the surface properly to remove any amine blush. In fact, a well-executed epoxy repair finished with a polyester gel coat is superior and longer-lasting than a well executed polyester repair. S sailsman63 Joined Mar 21, 2015 Messages 437 Reaction score 19 May 15, 2017 #7 The first polyester resin that we used was a lay-up polyester. I am having problem with the gelcoat drying. To thin the gel coat, use styrene monomer. Mais celui de l'edel est du evidemment du polyester insatur. I know Polyester and Epoxy dont meld well. 2. Gel coat is air inhibited and cures tacky on the surface to bond with the lamination. Too little catalyst will take too long to cure. But I believe the manufacturers use an Epoxy based primer that has similar properties to gel coat..However, based on the above information Gelcoat could be used as well. Gelcoat without wax, or any other air dry product that has been catalyzed with MEKP, will generally harden, but remain sticky. Example: If you rolled or sprayed polyester or vinyl ester resinon a surface of concrete, steel or any substrate, it would not hold water. It dries outward and under a microscope has small holes. Last edited by erospawn; Sep 29, 2016 at 08:49 AM. However, the gel coat does more than provide a glossy, attractive finish to the boat. Resistance to Wear. Likewise if you have the experience and can compare or contrast the effectiveness or projected life of new gelcoat vs. epoxy paint that would be of high interest too. ! Epoxy is more resistant to wearing, cracking and peeling, and corrosion or damage from chemical or environmental degradation. Gel coats & pigments add color, increase durability and enhance the appearance of composites parts. Re: bondo and gelcoat. Feb 24, 2012 72. Wash the fully cured TotalProtect or 2-Part Epoxy Primer with a mild soap and warm water. Ca te prendra a peu pres le meme temps de reprendre du debut que de tenter polyester sur epoxy. They are easy to apply in spray and roll and tip. Answer: Epoxy over Polyester does work if the surface of the gelcoat or polyester is properly prepared. This type of polyester resin had no wax and when we finished laying the fiberglass on the boat it remained very tacky. If the exact color you need is not available, a very true color "reproduction / match" can be achieved when mixing different color pigments together to "blend" into the color desired. so in this case. Jeff The epoxy first won't hurt, but I can't say for sure how much it will help. The gel coat is a polyester resin-based thermoset polymer or epoxy resin applied to the hull exterior in the fiberglass molding process. WARNING: Known to the state of CA to cause cancer, birth defects or reproductive harm - www.P65Warnings.ca.gov. Not sure if roll and tip works well. Correct application of gelcoat is critical to get the optimum performance from it. As near as I can tell, the bond is the same as over old polyester. Gelcoat is a big part of our business here at FGCI.When looking at gelcoat, there is a wealth of options to choose from. An epoxy's relative strength can hold up to 2,000 lbs. Epoxy is three to five times more expensive than polyester. If the gelcote cracked because flex was excessive, yes, it will fail again, over polyester or over epoxy. Gelcoat keels can be repaird in a couple hours and epoxy keels hang for days while individual layers slowly cure. Also note that while polyester will adhere to polyester, sticking to existing Vinylester or epoxy resin may yield different success. Secondly, they do not hold water or can contain a liquid. per quart of gel coat . Gelcoat is very expensive to apply, averaging $15-$20/sq. Gelcoat is formulated to be UV protective and stable against harmful chemical reactions. Boats that already have gelcoat, fiberglass, or polyester resin surface do not need any additional steps before repairing. I could not get as good a shine as I recalled from days of using polyester gelcoat with polyester molds. All of this material will remain tacky until it is no longer in contact with the air. The fiberglass and gel coat deteriorated in less than 60 days killing all the fish in the tank. Better adhesion and impermiability, easier to work over time, etc. Check the can that contained the gel coat .. is probably " non-air inhibited " gelcoat and wont 'set/cure' in full contact with air. Yes polyester has potential to shrink a lot. More gelcoat or polyester resin can be applied directly over this and still form a chemical bond while it still has a tacky feel. And yes, Bondo is not a good solution for most boat repairs; it does not flex much if any. Not as good as in-mold where they polymerize together, but the secondary bond is sufficient if flex is minimal. Gel coat is typically the first layer of a part to be applied. Turkuaz Polyester Gel Coats (Gelcoat) Sales Proportion of Gel Coats (Gelcoat) by Geographic Area in . The chemical bonding that allows gel coat to cure into the finished polyester part does not happen against an epoxy resin. I am appreciative of Adams mold polishing tutorials (slope forum IIRC). Evercoat Coloring Agents may be used to tint the material to desired color. Gelcoat is a liquid that hardens to form a thick layer that's used to protect fiberglass and give it a shiny, smooth finish. You can start with a 400 or 320 grit paper and gradually move up to say 800 grit. Gel coats are specialized polyester or vinyl ester resin formulations that are formulated as an in-mold coating to provide appealing cosmetics and protect the underlying laminate. First of all, Polyester and Vinyl ester resinsare the strength of epoxy. Sand with 120 and spray my poly. US Fiberglass Supply features an inventory of polyester resin, epoxy, gel coat, mat and cloth, foam and the various tools to aid in any lamination project. The hardener for gelcoat is the same as for any polyester resin methyl ethyl ketone peroxide, or MEKP. Other GelCoat Features For various reasons, some breakdown faster than others; however, they all deteriorate. Evercoat Mold Release (# 105685) must be used to attain a fully cured surface. Epoxy finishes tend to chalk on exposure to UV light, and the esters are really designed for gel coating or laminations. per gallon). The only conditions are that the epoxy needs to be thoroughly cured, well abraded and scrupulously clean. 47,184. Black Pigment for Epoxy Resin, Gelcoat, Paint - 4 oz. Epoxy paint is not known for its shine and finish. When the life cycle costs of gelcoat are added to the initial application cost, gelcoat costs about 2-3 times more than water slides resurfaced with the SlideRenu 3-Coat Water Slide System. This item: White Pigment for Epoxy Resin, Gelcoat, Paint - 4 oz. Gel coat is a colored resin that is buffed and polished to a durable gloss finish. Please 'Like' or 'Share' above and join the discussion below in our comments section! Flow Coat is formulated as a final coat that can be applied on top of layers or glass and resin. Rpondre Ulysse_66 19 jan. 2019 0 Merci pour toutes ces prcisions. 404. Finish the job by giving the repair area a fresh coat of wax.