|
There are three types of polyester resin. One is laminating resin, which as you've discovered stays tacky on the surface. That's so additional layers will have maximum adhesion. It will eventually fully cure on the surface but it takes a while.
The second type is finishing resin. It has a wax in it which floats to the surface, sealing it from air so it cures.
The third type is a "universal" resin. It has less wax than finishing resin so it surface cures slower and can have more layers added, but bond strength between layers can be compromised.
With finishing or universal resin, to add more layers, or primer/paint, after it's cured you need to scrub it with acetone to remove the wax.
And then there's gel coat, a thick resin with a lot of filler and color added. It's normally applied to the inside of a mold then backed with regular resin and glass or other reinforcement. It can be mixed and spread onto fiberglass then sanded and smoothed and polished and buffed to a high gloss - a huge amount of work but the result is a tough surface with a deep color no paint can match and it's possible to sand and buff out scratches.
|