Gel Coat Color

Is there a quick, generic way to color Gel coat for a mold? I am wanting a red or orange color. there are no fiberglass retailers near and I was thinking something from a paint store might work. Also what is the lowest temperature that I can spray?

 

Afraid not, you will have to use the correct pigment from a glass fibre supplier, perhaps whoever supplied your Gelcoat could help.

 

Best to get the correct pigment(s). One of the F/G manufacturers will do gel pigments, and these do have a very long life, unlike gelcoat. If you mix a custom colour, do so as a pigment so you can keep a small ammount back for guaranteed colour matched repairs.

Normally from 2-5% tint is used in the gelcoat. The pigments are not expensive if you buy say 0.5 Kg tins and a little goes a long way.

As for base temperature, you will need to check with the recommendation from the manufacturer, but I try and have at least 10 degrees C or higher to get cure. Remember if you are moulding to ensure that there is not any condensation on the mould surface prior to spraying. I have recently discovered osmosis on a couple of newish hulls where the builder has obviously not dried off the mould before brushing the gel into it!. You can see the brush mark pattern of the osmosis. Pretty rare to see these days, but something to be wary of.

 

The minimum temperature is 60* for gel coat, but 70* is better, especially for mold building. There is a difference between normal gel coat and tooling gel coat, but for limited use (one-off) molds you may get by with a normal gel coat, surface gloss and gloss retention may suffer though.

Tinting can be done, but depending on the color you are starting with you will be limited as to how much of a color change you will achieve. It's not hard to add too much pigment and degrade the gel coat, extra pigment can cause cure related issues, plus sagging and color separation.