hi, I’ve read swaylocks for a few months, but this is my first time posting. I got my hands on some pink construction eps foam about…8’ x 22’’ x 1.5’‘. It’s rather thin, but I think I could probably glue two of them together and it wouldnt be too much of a problem to make a sub 6’ stringerless board w/ expoy. I was reading the specs on the foam I found from their website, and I am quite confused about how strong it is. I’ve searched around and only found people talking about 1lb 1.5lb etc instead of what they listed as PSI. So I was wondering if you guys could tell me if this foam was strong enough to build a board with. Here are the listed infromation about the foam on their website:
oh, I forgot the mention, this foam has been laying around unprotected outside for at least a few months. It’s been raining pretty hard at least a dozen times, and it seems completely water resistant. It still feels super strong and light.
do an archive search for xps and you’ll know why you might have problems using that stuff
though XTR blanks are extruded (don’t think they use CFCs as a blowing agent though) and Patagonia’s are extruded as well (I believe). One of our members, MrJ, used it extensively with positive results.
Initially really good for a core material, but experience shows it gasses over a period of time, like 3 months to a year depending on heat exposure, and the board delams starting with big bubbles.
Seems strong, so a vent system, either mulitple stipple holes in the deck or a multiple valve system might work.
Since it’s almost waterproof, the air has a hard time migrating, so multiple vents is needed to cure the gassing problem.
Some peeps stiple for a better lam hold, then stipple again for air release, but small enough so water moisture doesn’t go into the blank when exposed to cold water.
Not quite proven, but cheap source of core material, you only lose out on the glass and resin, so why not?
Yes, that will release air directly under the holes, but the rest of the air trapped say…in the center will not be able to migrate there, and cause a delam.
That’s the nature of waterproof foam. It’s almost airproof too.
So how does Patagonia get around this? Or do they not? Is there a way to let the XPS cure so the gas blows, then glass it? What about using a mold release agent so the glass can be removed after the blank starts to blow…then reglass the blank? That would be time consuming…but would it even work?
No idea - the secret, or how long do they last. Sold 2. Still have one, its 6 years old or so. I doesn’t get in the water too often anymore, but there’s nothing wrong with it.
Instead of gluing two together in a big block, consider cutting out 1.5" thick rocker shapes and gluing them lap style so you will have a blank ready to cut – lap, like a balsa blank is glued up.
Well…I don’t know you or your foam, but if you make the blanks for Fletch, then, yes.
Its a little yellow. I repaired one ding in the tail where I got dropped in on & the guy ran over my board (behind me) until his fin met my rail & stopped both of us.
That was maybe 4 years ago, before I even knew the difference between EPS & XPS and when I cut the crushed glass & foam out of the ding, the foam was little beads. That has always confused me, because Point Blanks says ‘extruded’ and I thought all bead foam was expanded, but I don’t really care, as long as it works. And it does. I fixed that ding by cutting a clean wedge and 5-minute epoxying in a wedge of bead foam from a TV or a microwave or something’s packaging that I found at work. Then glassed over with West System epoxy from West Marine, whilch turned very yellow and took about a month to harden. And when it was cured, it took two months to sand…
I use better epoxy now, but, as in introduction, it was enough to take the mystery out of it.
One of my others was the last board Flecth sent to Pope for bisecting. When it was shaped, he called me & said it was too beautiful to cut in half (it was a custom) and said he hadn’t been getting along all that well with the Popes…I should have listened. I never actually even traveled with it, just took it apart to fit it inside a small car.
Im just some random kid that likes to experiment with things and build things. I duno, I randomly came across some free foam laying around. Im a starving college student, so being economically effecient could save me some money instead of buying the new shipment of eps foam at fiberglass hawaii for 100 bucks.
This is cut and pasted from the XTR website. Explains how they make the holes to vent the board.
"HOW THERMOVENTS ARE APPLIED TO THE SURFBOARD?
Javier has designed and also patented a special tool that reaches 200’F and penetrates the glass all the way to the foam. This tool is applied after the surfboard has been finished.
This tool is made with special needles that conduct heat to melt the outer layers of the fiberglass and resin without debilitating the surfboard. It takes less than 1 minute to apply the vents and they are almost invisible."
Sorry, Tony, I misunderstood. By ‘my foam’, I thought you meant you were one of the guys making Point Blanks blanks…
I don’t really know why theirs are called ‘extruded’. When mine opened up, it sure looked expanded to me. And it hasn’t delammed, which sounds more like expanded as well.
“Extruded” might just be a matter of semantics in Patagonia’s case…
This is cut and pasted from the XTR website. Explains how they make the holes to vent the board.
"HOW THERMOVENTS ARE APPLIED TO THE SURFBOARD?
Javier has designed and also patented a special tool that reaches 200’F and penetrates the glass all the way to the foam. This tool is applied after the surfboard has been finished.
This tool is made with special needles that conduct heat to melt the outer layers of the fiberglass and resin without debilitating the surfboard. It takes less than 1 minute to apply the vents and they are almost invisible."
Guys at T&C told me about that thing. They said it was over 3k for that item. Wonder if it works? and even if it solves the outgassing problem there is still the polyethelene in the foam to contend with that prevents a good bond. My friend shapes for Eric Arakawa and he told me the Soloman blanks that are made from XPS break quite often and I was in there a few weeks ago and saw one broken in half.
they keep it the vents kinda secret, but my friend who works a bit on construction tells me about small little vents that allow one way air flow out and nothing in. maybe those would work, unless the price is ridiculous