Hi, I wonder what’s the difference between epoxy gelcoat and polyester gelcoat ?
I have been working with epoxy gelcoat and epoxy resin for molds but find it rather expensive.
Is it possible to use polyster gelcoat with epoxy resin or do I have to use polyster resin with polyster gelcoat?

Best regards

Epoxy bonds quite good with cured polyester. The polyester/vinyester gelcoats however are designed to not fully cure at the outside, to give a reactive surface with the backing polyester. As epoxy is chemically very different to polyester, it doesn't react with the surface, leaving it partially uncured.