Will fiberglass resin eat through foam?

bowfisher8967 · Dec 17, 2011

I want to glass the foam blocks that were under the seats in my jon boat (dont ask why. my business is my own! hah). Will the fiberglass resin eat through the foam before it can cure? I'm not sure if i'm using poly or epoxy resin yet. I'm not quite sure how to describe the foam... It is somewhat rigid but easy to poke a hole in with your finger. Kinda brittle though... could snap in half with a kick. Its kinda like what you would find at an art store for building science projects with... you can stick wooden dowels in it and make a model of an atom or whatever. Oh and it is green which i doubt makes any difference, but yall are the experts. Any advice is appreciated. This is my first glassing project.

bowfisher8967 · Dec 17, 2011

Re: Will fiberglass resin eat through foam?

Just to be clear, this stuff is buoyant. Completely different than the foam used at the bottom of floral arrangements.

andgott · Dec 17, 2011

Re: Will fiberglass resin eat through foam?

It depends on the foam. Usually, epoxies won't hurt foam. SOME foams are compatible with Poly resins, but not all- The styrene is pretty nasty stuff and it'll destroy a lot of foams. You'd probably have to experiment to be sure.

oops! · Dec 17, 2011

Re: Will fiberglass resin eat through foam?

yuppers it will........wrap the foam with packing tape...and you are good to go

tpenfield · Dec 17, 2011

Re: Will fiberglass resin eat through foam?

Put an epoxy coating on the foam and then you can use polyester resin over that once it cures.

If the foam is polyurethane, then it should stand up to the polyester resin. If it is polysytrene foam, then it will become a pile of gooo.

Woodonglass · Dec 17, 2011

Re: Will fiberglass resin eat through foam?

Nope, sorry this ^^^^ will not work. Poly will NOT adhere to epoxy. OOPS is correct, just use clear packing tape and the glass it.

tpenfield · Dec 18, 2011

Re: Will fiberglass resin eat through foam?

Woodonglass said:
Nope, sorry this ^^^^ will not work. Poly will NOT adhere to epoxy. OOPS is correct, just use clear packing tape and the glass it.

Who needs it to adhere? It is merely for the barrier purposes, like the packing tape.

oops! · Dec 18, 2011

Re: Will fiberglass resin eat through foam?

but epoxy is expensive and takes 23 hours to cure.

tape is a dollar at a dollar shop and done

bowfisher8967 · Dec 18, 2011

Re: Will fiberglass resin eat through foam?

Ok thanks. Would you recommend poly or epoxy for a marine environment (non-saltwater)? For an add-on on the exterior of my jon boat.

Woodonglass · Dec 18, 2011

Re: Will fiberglass resin eat through foam?

Is your jon boat fiberglass or aluminum?

SteveMcD · Dec 23, 2011

Re: Will fiberglass resin eat through foam?

My dad used to have, belive it or not, a styrofoam sailboat. The hull broke when we moved across country, and he tried to fix it with epoxy and fiberglass. The epoxy destroyed all of the foam it touched. Small scale experimentation first might be in order.

Mike Lammert · Dec 23, 2011

Re: Will fiberglass resin eat through foam?

SteveMcD said:
My dad used to have, belive it or not, a styrofoam sailboat. The hull broke when we moved across country, and he tried to fix it with epoxy and fiberglass. The epoxy destroyed all of the foam it touched. Small scale experimentation first might be in order.

I just built a new box for my flip/flop seat back which will be upholstered over...I stacked (4) 3/4" styrofoam sheets with epoxy resin between each, with 1/4" plywood skin, also epoxied....none of my styrofoam was eaten or weakened in any way.....very very strong finished product!

ondarvr · Dec 23, 2011

Re: Will fiberglass resin eat through foam?

SteveMcD said:
My dad used to have, belive it or not, a styrofoam sailboat. The hull broke when we moved across country, and he tried to fix it with epoxy and fiberglass. The epoxy destroyed all of the foam it touched. Small scale experimentation first might be in order.

He most likely didn't use epoxy.

Will fiberglass resin eat through foam?

Seaman

Seaman

Master Chief Petty Officer

Supreme Mariner

Moderator

Supreme Mariner

Moderator

Supreme Mariner

Seaman

Supreme Mariner

Petty Officer 2nd Class

Petty Officer 2nd Class

Supreme Mariner