Re: EPS Compsand board: Glassing only on outer surfaces? (deck & bottom) | Swaylocks

Sorry about the double thread but I can’t manage to use the reply button. It’s just dead.

 

I’ve edited my previous post just to add a couple of comments and say thanks!

 

My intention was to make a 9"2’ noserider using EPS sheets and insulating them with 1/8-inch marine-grade plywood skins & rails to allow glassing with poliester resin without the whole thing burning up.

 

EPS/XPS is cheaper and so is poly resin so that’s the main practical reason. Also, it would be like a hollow wooden board in which foam replaces the air, therefore no need for a vent hole.

Three problems solved?

Oh, and a 1/3" stringer too.

 

I wish that reply button would work!

 

Thanks for your replies on this and on the original thread. I won’t be able to reply myself though.

When you get 10 points you’ll be able to reply. I upvoted you a couple points on your two threads.

I’ve found that 1/8" ply is heavy. My board was only 7’ long and 2" thick, but it was noticably heavier. I only did the bottom with the ply as a time saving test. We normally make the skins from model airplane balsa sheets. This was made with light EPS insulation foam from Home Depot or Lowes. I think I tried doing the simplest cheap way and used a single 2" thick slab of foam bent in the rocker with the bottom lam, then added wood rails and a balsa deck skin.

I would look for a cheap epoxy resin, and laminate the board without the ply, then paint over that. Just use more fiberglass, like 3 layers for the deck or go with a heavier glass. I’ve done double 8 oz glass, and triple 6 oz on 1 lb EPS. It still dents easily, but it will be lighter. Or try to thin out the ply with a thickness planer.

Yes, I’ve thought of going for the cheap epoxy —which in my area is a horrible pinkish one— and then paint it over but i find that shaping wood (in this case just the rails) is a bit easier for me than doing such a long blank with an increased risk or ruining it.

 

And bending the foam into the rockered bottom ply was something I was pondering too. Good idea. (you said “bottom lam” but I assume you meant “ply”?)

Weight would not be too much of an issue for me as it’s a longboard, so nothing like the lightness you’d expect from one of your shorter balsa-skin boards.

 

I’ve done a back-of-the-envelope calculation on a spread sheet and it would end up weighing about 7kg (or just about 15.5 lbs) before laminating, which might not be too much on the heavy side for a noserider.

 

I’ll be making my mind up this week before the cold weather creeps in.

Good night.