Bill 404 wrote:
Well, the West System did not adhere to my hull and I peeled it right off
That may have been due to some residual wax on the surface or a resin/hardener mix that was off. WEST is fairly sensitive to the 5:1 ratio - it will have a rubbery cure if the mix is off. Epoxy also takes a long time to come to a final cure (week or longer).
Bill 404 wrote:
....so what product is suggested to work well with my gelcoat. I am trying to build up a small area maybe 5" X 12" that needs material prior to having my boat re-gelcoated by my local dealer.
Definitely polyester - it's what the boat's made of - and it's compatible with gelcoat (which is also polyester). Gelcoat over epoxy can be tricky. When epoxy cures, it develops an amine blush (especially in humid weather) on the surface that's like a wax. It has to be thoroughly cleaned with solvent and the surface profiled (sanded) before going over with gel. Even then, it might not work and all you've done is create a mess.
Since you're not doing anything structural, vinylester is just a waste of money.