Can you use a polyester gelcoat with epoxy resin.
as long as the epoxi resin is glueing into a cured poliester gelcoat it is possible and normal procedure but you can not do it the other way round, I mean the poliester will not stick well to cured epoxi
I agree but talking from personal experience make a test panel first, because there are epoxies and gelcoats which are not compatible.
Epoxy adheres well to cured epoxy and polyester.
Polyester does not adhere well to anything, even to itself.
I’d say to scratch up the inside of the gelcoat (if you are working inside a mold) for the epoxy to have more “grip” to the cured poylester surface.
Sandblasting is a great way to get a very good “adhesion surface”.
thanks for the advice, very helpful