I have been building quite a few eps/ epoxy boards with Resin Research and 2lb eps foam with great success. However, when laminating Clark or Rhyo foam with epoxy resin, I have found that the boards are coning out softer. They are significantly softer and dent like crazy. Luckily we have only experimented with team riders boards. If you search the archive you will find information that says epoxy over clark foam in stronger than polyester resin over the same urathane foam. In fact one distributor says," Its Much Much Stronger." If you start adding double layers of glass to the bottoms and triple layers to the deck as if it was an eps lamination, the board will begin to gain significant weight. Any thoughts?
I found that Epoxy over PU was either softer, not fully reacted, or brittle.
Some sort of reaction with the polyols in the foam and the hardener in the
epoxy. Look for Rich Harbour’s experiences with epoxy over PU…
…pretty much the same thing.
Okay, with that said, there might be ways to get it done. I had some
success using a “tie coat”. An effective tie coat between the two is
linear polyurethane in liquid form. I hated the toxicity.
As a second suggestion here is something I haven’t tried. Sealing the
PU blank with a coat of epoxy and cooking it pretty good to try and get
a more complete reaction. Then glassing the board with epoxy and using
a post-cure oven. (seems that PU draws heat somehow rather than insulating
like EPS does, and this affects the post-cure reaction).
Curious to see if this is successful,
George
George,
Some of the guys trying the PU/Epoxy are cheater coating the blank. But the JF Blanks don’t seem to mind the length of time to cure (baking is way better) with little soakage. I would suggest cheater coating, just a quick pass to seal it.
I hope you will post the results from your newest experiment with the Just Foam PU blanks and epoxy once you’ve finished.
I understand you have been so cold you were considering some very nice sweaters with Plus One insignia. Maybe Boy George style. Go George.
Bubba
My statement above was before learning about the new PU formulation. I plan to
start that test as soon as some of the dust settles in about a week.
'til then, you got a hammer I can borrow? (very cold this morning)…
i have found that the revchem epoxy work better because it is a little thiner and kicked a little faster with out to much exotherm but the boards dont seem to be much stronger but if you go by the numbers they should be ??? any thought…
One hammer coming up, wrapped in a very nice Gucci Sweater.
Hey RICHARDL
I think the temperature of the room where you are glassing is VERY important.
Even AFTER glassing, the temp should not (IMO) drop until the board is complete.
This alone makes a stronger board, you will notice the difference. If you make
one and it gets cooler at some time during the process, the board will still
feel firm, but it most likely will not be as strong as it could be…
Are you post curing them?
FWIW I’ve glassed a couple of Clark blanks with RR epoxy and it seemed that once complete cure was achieved (no oven or post cure) the single 4 oz bottom was about as hard as 6 oz with polyester. I did my typical double deck with patch and pressure dents don’t seem to be a problem.
Also glossed with poly over rough sanded epoxy fill coat and no problem with that either.
I have had bonding issues with epoxy over epoxy when glassing in colder temperatures than recommended. The epoxy went off OK but blushed enough to create little delam bubbles between the glass along the rails when even slight impact occurred. Slight delam bubbles between fill coat and lam also but minor compared to rails. My first clue that something was haywire was when sanding the overlaps after fill coating - I noticed some flaking occurring instead of feathering.
I only bring it up since I know it’s getting colder in US where some of you might be using epoxy. Build a hotbox or figure out a way to keep temperatures above the 65 minimum for the full duration of the cure.
Maybe consider the lam-fill-flip-lam-fill method rather than the lam-flip-lam-flip-fill-flip-fill method? It decreases the time lag between coats.
The PU foam formulations are something I wasn’t aware of but if it affects epoxy cure, maybe an epoxy expert like Greg Loehr can can provide more details? The old Clark Foam formulation was not a problem with epoxy that I know of.
I am hearing the main reason Clark foam and Epoxy never took off was the delamination was bad. The Clark (and now US Foam) would actually delaminate from itself, not from the epoxy (or from the polyester either). Just what I have heard from a number of guys who tried it before Gordon shut down.
You should not use epoxy in any cold temps, the warmer the better, including baking it at over 100f when possible.
here is a great PU blank you can get right here in Florida…it comes with a 5 gallon bucket of spackle
Adam,
Where did that come from? Looks like it should be really light with all the air helping it out.
We’ll have Just Foam Blanks available in Florida very soon, from a reputable distributor. Feel free to go to our website www.justfoamblanks.com, we’ll annouce it as soon as we have completed the deal.
Scott
lets just say the company is downsizing
A guy who listened to mom when she taught us all, “if you don’t have anything nice to say, say nothing.” Good for you Adam.
You know it’s ironic, many of the current foam companies have had similar (but smaller) problems. Lightweight surfboard foam is just a very difficult product to manufacture consistently.
“lets just say the company is downsizing”…
I was waiting for a comment like “Florida Swiss Cheese” or something…
(Sorry for my comment, some people (like me) just ain’t got nooo class).
it’s hard not to throw the name out there but if you read all the sections of swaylocks you should be able to figure it out with one key word. when I get done with it i’ll post more pictues