Epoxy on eps is soft?

I'm glassing with epoxy for the first time. I used 6oz fiber glass and epoxy that is 1:1 on my eps. It's soft, I let it cure and still the next day its soft, not wet, but soft. Is this normal? After the hot coat, will this harden up or should I put a layer of poly on it, or would that even help?  Please someone tell me what's up!

Yeah, in my experience (which is anything but vast) 1 layer of 6 oz on EPS will be soft. The last board I did I put 3 layers of 4 oz on deck, plus 4 oz patches under the front and back feet. In my case even the 4x4x4 was still deformable by applying pressure with the thumb. So i went and added the deck patches later.


If you used 1lb eps foam, it will be stay soft unless you glass it very heavy.

If you used >2lb eps foam, this is not normal, what do you mean by soft?


edit: never used eps in a non-compsand, but 2lb xps is pretty rigid

I really don’t know what the poundage is. I’m in Nicaragua and to ask what type of EPS is, they would tell me white. I do think it’s only 1Lb, mainly because it’s the construction norm.


Do any of you think the adding poly over the epoxy would harden it up? I’m thinking I’ll seal with epoxy and glass with poly. What’s your thoughts? I can only get this type of foam here, as far as my extensive investigations go!

Poly over epoxy is a bad idea!

To know the density put it on a scale, some basic math and you know it.


If you want to make it stronger put some more glass on with epoxy.

The construction/insulation EPS is very soft, so a heavy(ish) glass schedule should do it. And like hans said Poly over EPS is a bad idea.

Just add another layer or two and glass using epoxy. It'll be fine.

Thanks brothas! Will do thicker and more glassing, it is.

on super light wight eps for insulation, wich you have maybe, i glassed with double 6 bottom and 4 top. strong enough. maybe 3 on top wil be enough…


good luck



1 lb foam is useless in surfboard construction...unless you are vac bagging and doing skins.  1.5 or 2 is so much better.  If you have to use 1 lb because you live in a far away place. then you better do a 3x6 top and a 2x6 bottom. Even that will get heel dents. 

1 lb foam foam sucks.  Better used in construction.

I’m feeling your pain, Benito. I live in Costa RIca and I’ve only found the light weight EPS here as well. On the last board I did 4x4 on top with an additional deck patch and that was enough to make it rideable, but I still feel like I’m on a ‘soft-top’. I tried to poly on epoxy and that was, in fact, a ‘bad idea’. On the up side, the stuff is so friggin’ light that the board isn’t heavy even after all that glass. 


I’ll be in Panama in a few weeks and one thing I’m planning to check on is the availability of 1.5 or 2lb foam.