Something that I want to emphasize is that the above steps are not only geared to epoxy. Panels were covered with 879 Release Fabric and allowed to cure. Various Types of Polyester Resin: Gelcoats are modified resins which are applied to moulds in the liquid state. Also I have heard West system, the one used in the video, is one epoxy that can be used under gel coat. Gel coats are polyester resins and will not adhere well if epoxy resin is used first. I am using a male mold to build a bimini covering for my center cockpit sailboat. Discussion in 'Fiberglass and Composite Boat Building' started by grady, Jun 4, 2014. Or is there another product you can suggest? Polyester pigments can be mixed with Polyester resin and Polyester Gelcoat, Epoxy pigments can be mixed with Epoxy resin and Epoxy gelcoat. 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. Epoxy can be compatible with Gelcoat but there's too many variables for me to be a fan of using it. Epoxy bonds quite good with cured polyester. Polyester resin will not cure on the surface in the presence of air. Unlike conventional polyester gelcoats, which epoxy resin cannot bond properly to, GC50 cures dry to the touch on the open face and can be fully bonded to by epoxy resin. I just bought what the guy Im buying it from said would work. Since these three modes of failure occurred under similar loads, it indicates that the strength of the bond is close to the cohesive strength of both the gelcoat and the fairing compound. For applications under the waterline a thickness of 20-24 mils aids in blister prevention and is better than thinner layers. Basically, there are only two types of fiberglass resin. Therefore, items constructed with these materials should be repaired with the same or compatible material. Most production fiberglass boats are made with polyester resin, and we're often asked if it's appropriate to use polyester gelcoat over epoxy. Sold as a kit (resin and hardener). Figure 1. Correct me if I am wrong. How about jelcoat in a femaile mold, prep as in the video, then make a Kevlar/epoxy boat? How to successfully apply a gelcoat finish over WEST SYSTEM Epoxy. Epoxy is more resistant to wearing, cracking and peeling, and corrosion or damage from chemical or environmental degradation. Gelcoats & Paint. Gelcoat is an epoxy or polyester resin-based thermoset polymer that is usually applied to the boat exterior during the fiberglass molding process to give a smooth, shiny appearance. In stock. Check out his web site for all the details. Polyester Gelcoat is used to provide a high-quality visually pleasing finish on the surfaces of a fiber-reinforced composite material. Where there are structural cracks in the concrete substrate, a 13-oz/.37-kg woven roving mat is layed up over the damaged area before FRP spray up begins. This is the final video testing to see whether gelcoat can be successfully applied to epoxy. Two popular gelcoats were used, Minicraft and Evercoat. Here is the first of 2 videos where I look to see if theres any truth to the belief that polyester based materials (such as gelcoat) wont bond to epoxy. Available in 9 popular colors, sold separately, or as a kit. 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. http://gougeon32.blogspot.com/search?updated-max=2016-02-16T07:51:00-08:00&max-results=10&start=6&by-date=false. Interestingly, Evercoat states on their can that it is not to be used over epoxy. Each data point represents the average of five stud pulls. Sep 17, 2017. Crystic Gelcoat 253PA is designed for use with wet lay and vacuum injected epoxy systems. Once cured, EG60 is hard-wearing, chemical resistant and a suitable tool surface for the production of epoxy-based parts. One gallon of gelcoat weighs approximately 10.5 lbs. Panels were then placed in our 100% humidity/100F environment room. It is done, though. Hi, I wonder whats the difference between epoxy gelcoat and polyester gelcoat ? per gallon). This test confirms that polyester gelcoats can be applied over cured WEST SYSTEM epoxy on repairs below the waterline. Copyright document.write(new Date().getFullYear()) Website Acquisitions Inc. All rights reserved. Each resealable bottle contains 2 oz. In critical applications MEKP should be measured using cc's or fluid oz's which are volume measurements. Best regards. If you want to roll on a gelcoat, be sure to use a 1/8 "or 14" solvent-resistant nap. Gelcoat provides more than just a glossy finish on the boat hull; it also acts as a waterproof barrier to protect the fiberglass underneath from hydrolysis and UV . Gelcoat IS a Polyester based product so this is the Main Reason to do the repairs to your Polyester Resin Hull. It is brushed on and then flecked with a spray gun. 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. Such a situation might occur with a boat kept in a pristine lake where antifouling paint is often not used. Most DIY owners are typically working on boats that have a gelcoat exterior, which is what the focus of this experiment was geared towards. Gelcoats are modified resins which are applied to moulds in the liquid state. | Developed by Fortiris Group LLC. Just wondering why you did not test the high build???? Choose from White, Black, Dove Grey, Bright Blue or Dark Olive. Simple.. Check with your polyester gelcoat supplier for recommendations and test to determine product suitability and application technique. However, customers often want to restore the original gelcoat finish to below-waterline repairs where the boat is kept in the water and no antifouling paint is applied. Forum posts represent the experience, opinion, and view of individual users. I have just completed a repair using the west system. If the repair is above the waterline, high-gloss paint or gelcoat are often used to reproduce the original appearance. Since the polyester gelcoat is not very good at preventing moisture from permeating through to the laminate, there has been a concern that, over time, the gelcoat will detach from the more moisture-resistant epoxy layer. The overall effect of moisture on the gel coats bond to both the polyester and epoxy panels was negligible. 2. Or do I need to coat with Petitt protect. Scrub the surface with clean water, wipe the surface dry with a clean papertowel and this detail is taken care of. It claims it kills the blush. For full size boats, sometimes a layer of vinylester is used between an epoxy hull and the gelcoat. Resistance to Wear. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Because Boatworks Today, its owners or partners cannot control how the information provided through these videos is applied, we will not be held liable for any damages; incidental or consequential. Can I coat the EZ-Fair with 105 Epoxy Resin let it set then finish off with Gel-Coat? Those of us using epoxy never put gel coat directly on top the epoxy. Formulated for brush application. The graph for each combination shows the tensile load required to pull the stud off the panel at four time intervals, illustrating the trend of the bond strength when the gelcoat is applied after allowing the laminate to cure for 36 hours and 7 days. It has a . Gelcoat derives its name due to it high viscosity and ability to be applied thickly on vertical and overhead surfaces in one coat. This laminate provided a stiff panel that simulated a patch used to repair the bottom of a fiberglass boat. VIBRANT COLORS blend easily into epoxy and polyester resins, and won't fade or discolor VERSATILE PIGMENTS are ideal for a variety of marine, woodworking and craft uses. Polyester resin laminates achieve their highest strength when the bonds between layers of fiberglass are chemical or primary bonds as opposed to mechanical or secondary bonds. The first layer of the laminate is then applied to gel coat, which has not completely cured. How ever any good modified base enamel will bond to either product and can also be used with anti skid if you need to use it SuzukiChopper Senior Chief Petty Officer Joined Oct 10, 2004 Messages 782 Nov 7, 2004 #3 Re: Gelcoat over epoxy? For epoxy resins you could use nitric acid or dichloromethane. Thanks good point I havent thought about that. Second issue. After the Release Fabric was removed, a variety of finishing processes were applied to the panels. Epoxy is a very superior material to polyester for use on underwater repairs for all reasons. Laminating resin (small cans) first, scrape with razor, mask, top a bit high with gelcoat, put clear tape over to cure hard, sand and buff until happy, maybe a little wax or something to seal and polish. As with many products, the surface must be prepared properly; if it is not, then poor curing and adhesion may result. We generally use a high build epoxy primer, and then a finish primer and then a 2 part polyurethane. These customers are concerned about the gel coats long-term ability to adhere to the area repaired with epoxy. For more details please visit our website. Laminate a square of epoxy and glass up one end. A hour or two later lay up another patch. The most common gelcoats are thermosetting polymers based on epoxy or unsaturated polyester resin chemistry. A wide range of Epoxy and Polyester colour paste pigments are available. For . Gel coat is used as an in mold coating on composite parts to produce a durable part surface. Once the EZ-fair is properly shaped I would like to finish off with Gel-Coat. Dont listen to the critics about your videos, the education of these products are money saved in my pocket. Gelcoats are modified resins that are applied to molds in a liquid state. This coating is allowed to cure and the epoxy laminate is applied directly to the paint. Its aways best to apply glass onto glass (when possible). The nine-week exposure may not simulate what could happen after many years, but it does indicate that the gelcoat bond to epoxy laminates is a good bond and should perform well. Jul 18, 2014. Woven roving can be added during the spray-up process for strength improvement in a specific direction or location. It's been long believed that if you were using epoxy for your fiberglass repairs, you were more or less limited to having to use paint as your topcoat. It's always a safe bet to keep similar products together. http://epoxyworks.com/index.php/polyester-over-epoxy/, (You must log in or sign up to reply here.). I am preparing to build a trimaran using a similar technique but his renovation has given me pause. They claim that you can use it as a tie Coat. ADDRESS Unit 17 & 20 Abbey Business Park Mill Road, Newtownabbey Co.Antrim BT36 7EE CONTACT phone 028 90 861992 email sales@mbfg.co.uk The polyester/vinyester gelcoats however are designed to not fully cure at the outside, to give a reactive surface with the backing polyester. Is there any truth to the idea that polyester based material won't bond to epoxy? A layer of resin . Materials for spray-up molds may be wood, vinyl polyester, epoxy, rubber or steel. The person doing it is a professional boatbuilder and was working closely with West Systems people in consultation. September 15, 2019. Suitable for application by brush to give an even film, free from air and drainage. http://gougeon32.blogspot.com/search?updated-max=2016-02-16T07:51:00-08:00&max-results=10&start=6&by-date=false by Jeff Wright Vice President of Technical Services. If you will be finishing with a gel coat, it is important to use either polyester or vinyl ester resin as your laminating resin. Epoxy has a lot of appeal for repair work (extended work times, stronger mechanical bonding, better moisture protection, etc). We can give you perfectly matched c. Boat Design Net does not necessarily endorse nor share the view of each individual post. Gel coat is air inhibited and cures . It is not recommended for use in any application which is subject to continuous immersion in water. MEK Peroxide Catalyst for Gelcoat/Polyester 2 ounce $ 3.99; Add to cart; Polyester Resin, 1 Gallon $ 50.98; Add to cart; Facebook Youtube Envelope Instagram . We stock a wide variety of colors in marine and tooling gelcoat. Im not saying that its common practice, but in certain circumstances its something that I have done successfully.