Poly Resin Question

[bigredinohio]

Strange question but I was wondering if I could lay a layer of glass with epoxy resin over top polyester resin without the wax curing agent or if poly needs to be completely cured beforehand?

 

[ondarvr]

Re: Poly Resin Question

What is it you're trying to do?

 

[bigredinohio]

Re: Poly Resin Question

Lay a layer of glass to the inside transom skin using poly to cover holes then another layer of over that with epoxy. Then transom install with pb made of epoxy...etc. I wanted to use poly for the first layer so I'd be able to gelcoat the boat, should I choose to.

 

[ondarvr]

Re: Poly Resin Question

The layer of polyester should be sanded thoroughly before putting epoxy over it.

Two reasons

If there's wax in resin it needs to be removed and the surface under the wax can be difficult to bond to without sanding.

With no wax there is a very thin uncured layer of resin on surface, this works well when using polyester over it because you will be getting a chemical bond. With epoxy there will be no chemical bond, the chemistry is just too different, so this uncured layer becomes a barrier not allowing the epoxy to bond to a solid surface. So once again it needs to sanded.

 

[bigredinohio]

Re: Poly Resin Question

Thank you ondarvr! I"m sure it's been said before but your knowledge is a wonderful resource on this forum.