About Gelcoat
Gelcoat in general:
Gelcoat is mostly polyester resin with a lot of pigment added. It cures with the same catalyst and is chemically compatible with most of the products we sell. It's frequently used as paint, but if you decide to use it as paint there are some important caveats you should be aware of which we'll discuss below.
In general you should use the same or slightly more catalyst when mixing your gelcoat. A bit more catalyst should result in a slightly harder surface finish on the gelcoat which is nice if you plan on sanding and buffing it.
Wax vs Non-waxed Gelcoat
Gelcoat is typically applied in a mold and has a layer of fiberglass applied over it, to make this work the chemistry in Gelcoat is "air-inhibited cure" which means that it stays sticky for the next layer to bond to. If you'd like to use gelcoat as a paint you must add WAX to the gelcoat to block the air and allow it to cure fully. We sell gelcoats without wax and with wax, along with separate wax to add to the gelcoat yourself.
Waxed and Non-wax gelcoat is also known as Interior and Exterior gelcoat respectively, the nomenclature is slightly backwards but it makes sense if you think about the gelcoat being applied to a mold.
Gelcoat as Paint
Gelcoat is frequently used as a paint. If this is in the inside of the boat usually a texture is acceptable but frequently you'd like to paint something on the outside in which case you'd like a smooth surface. A thinner must be used. We like Duratec Clear Additive it's formulated to thin the gelcoat and allow it to be sprayed without damaging the UV protection the gelcoat offers. Acetone will NOT work.
By: Capt. Ken