Can fiberglass be safely laminated to gel coat?

[Darren Nemeth]

For my Batboat overhaul I need to replace the air scoops, those things that look like "eyes" on the bow. [illustrated in the attached image]

In order to do this one of the things I need to do is peanut butter fillet new air scoop panels along the sides, topside.

Will I be able to securely bond these new forms using poly resin and wood flower mixture directly to the gel coat or will I have to grind the areas down to the fiberglass??

Thank you in advance.

 

[ondarvr]

Re: Can fiberglass be safely laminated to gel coat?

Yes, maybe, sort of, not really, but kind of.

Are you only using the putty to bond them on, or are you bonding them in place with the putty and then glassing over it. There are different answers depending on the situation.

The proper way is to grind it down to the glass for the strongest bond, but on something that isn't going to have any stress on it, bonding to the gel coat is OK. Gel coat is made with resin, so the bond is very good, the problem is there are no fibers in the gel coat, so its not as strong as the laminate itself.

If you are just basically gluing them in place, use an adhesive, it will work much better than polyester putty.

 

[Darren Nemeth]

Re: Can fiberglass be safely laminated to gel coat?

Yes, maybe, sort of, not really, but kind of.

Are you only using the putty to bond them on, or are you bonding them in place with the putty and then glassing over it. There are different answers depending on the situation.

Will be using poly or epoxy resin mixed with wood flower. The side sections of the air scoops will be clamped or screwed to the topside until cured.

The proper way is to grind it down to the glass for the strongest bond, but on something that isn't going to have any stress on it, bonding to the gel coat is OK. Gel coat is made with resin, so the bond is very good, the problem is there are no fibers in the gel coat, so its not as strong as the laminate itself.

That is what I was kind of worried about.

 

[erikgreen]

Re: Can fiberglass be safely laminated to gel coat?

You can glue to gel coat with epoxy putty just fine, but the strength of the joint that holds your part on is limited to the strength of the bond between the gel coat and what's underneath it (the epoxy is grabbing the gel coat, not the fiberglass).

Kinda like gluing something to a painted object, you want to make sure the paint won't peel because if it does the thing comes apart easily.

 

[Darren Nemeth]

Re: Can fiberglass be safely laminated to gel coat?

Thanks. I grind it down to the fiberglass then.

 

[drewpster]

Re: Can fiberglass be safely laminated to gel coat?

one more, also remember, if your using epoxy the bond to the surface will be MUCH stronger than poly and flour. Epoxy's ability to bond is superior to polyester. but either will work