It is not often used as a post-production finish coating, but it can be applied over epoxy and is useful in some repair situations. 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. Polyester gelcoat is a pigmented version of the resin used to build fiberglass boats and other products. Self-etching primers do not work well on an epoxy coating because of epoxy’s chemical resistance. If the instructions on your paint or varnish recommend a specially primed surface, follow the recommendations given for fiberglass preparation. Primers are usually not needed to help a paint film bond to epoxy, although interfacing primers may be required with some specialized bottom paints and high-build primers are useful for hiding scratches or flaws in the substrate. ![]() Other paints including marine LPs and primers, are not recommended for use below the waterline. ![]() ![]() Follow the recommendations given for preparation of fiberglass surfaces. If you are unsure of compatibility or have curing or adhesion problems with a specific bottom paint, use only a primer recommended for that bottom paint over the barrier coat. Most bottom paint systems are compatible with epoxy and can be applied directly over a prepared epoxy barrier coat. However, compared to other types of coatings, they are expensive, require more skill to apply and present a greater health hazard, especially when sprayed.īottom paints are available in a variety of formulations. LP paints are available as pigmented or clear coatings and offer excellent UV protection, gloss retention, abrasion resistance, plus compatibility with epoxy. Two-part linear polyurethane (LP) paints offer the most durable protection available. They are durable and chemical resistant but offer limited UV protection compared to the linear polyurethanes. Two-part epoxies offer many characteristics similar to the higher performance polyurethanes. Test first.Įpoxy paints are available in one-part and two-part versions. They are also more expensive and some may be incompatible with amine cure epoxy systems such as WEST SYSTEM epoxy, although 207 Hardener may offer better compatibility. One-part polyurethanes offer easy application, cleanup, and better properties than alkyds. Their disadvantages are low UV resistance and low abrasion resistance. Their durability is limited.Īlkyd finishes-enamel, alkyd enamel, marine enamel, acrylic enamel, alkyd modified epoxy, traditional varnish and spar varnish-offer ease of application, low cost, low toxicity, and easy availability. In many architectural applications, latex paint may be the most suitable coating to use. Latex paints are compatible with epoxy and they do an adequate job of protecting the epoxy barrier from UV radiation. However, it is still a good idea to build a test panel to assure coating compatibility. This means most paint solvents will not soften, swell or react with it. Thoroughly cured epoxy is an almost completely inert hard plastic. Most types of coatings are compatible with epoxy. ![]() All other thing being equal, a white (especially a glossy white) coating will last the longest. A high gloss finish reflects a higher proportion of the light hitting the surface than a dull surface. Long term UV (ultraviolet) protection of the barrier coat depends on how well the finish coating itself resists UV and keeps its pigments or its shield of UV filters on the surface of the epoxy barrier coat. Protection from sunlight is a primary consideration in the selection of a finish coating. Together the two form a protective system far more durable than either coating by itself. The finish coating extends the life of the epoxy moisture barrier, which in turn provides a stable base that extends the life of the finish coating. Finish coatings protect the epoxy from sunlight.įinish coatings like paint or varnish are applied over an epoxy barrier coat to decorate the surface and protect the epoxy from sunlight.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |