I can’t believe I’ve never come across this, but is the density of EPS per cubic foot? Like a 1’x1’x1’ block of “1lb foam” will weigh 1 lb?
I have a line on a good deal on some billets, but the guy doesn’t know the density. Should I just weigh them and divide by the cubic footage?
You got it right!
shwuz,
If you measure the block(s) real close you will find that they never weigh what they are rated at. We used to get some real good 1# for sailboards and it would weigh .75-.85 #/cuft. This was desirable for the sailboards. I don’t think I have ever got any 2# that actually weighed that either. Always a little lighter. You can even take scraps and measure carefully and do the math and get the density.
Dave_D
Cool, thanks for the info guys!
So, if I’m hoping for 2lb foam, I’m expecting a 8x2x2 billet to weigh 64 lbs. Maybe a little less, if dave_d’s experience holds true. How much lighter was it running? A quarter pound, tenth of a pound? Just looking for some guidelines on what to expect.
Thanks for the quick replies everyone.
The 2# we were getting from Carpenter seemed to run around 1.75-1.85 # a cu/ft. I never weighed the entire blocks as we were getting the full billet out of the mold which is roughly 3’ x 4’ x 12’. I would weigh scraps and measure them carefully in inches and do the math from there. There was never any problem with the foam that wasn’t quite 2#. In fact when we ran into problems was when trying to get 2# C bead from them. It was total crap and they took it back and I gladly got more of the 1.85# stuff I had been using. The best eps in big blocks I ever got was from Greg L which came from Imperial in Fla. If you have ordered RR from Sam I’m sure you have seen some of their scraps in the box with the resin. It is very nice foam.
Dave_D
They are allowed a 10% margin of error plus or minus, so expect to be 10% less in weight. Look for bead size variance. Bigger beads tend to tear out worse than little ones in my experience. The foam supplier I’ve been using says that the guys running the press will ALWAYS go lighter than what the density is supposed to be.
edit: The 10% number is what I heard, but the math comes out right. I was told 1.8 lb EPS is commonly sold as 2 lb.
<repeat of info above>
It’s not a stupid question…
Five years ago I thought that only kooks built boards from EPS/Epoxy. Now I push people to build boards with these materials…
My first block of foam came from Chino California. Remember the thread where some So Cal and San Diego people got together to buy a block of foam??? My second block of foam I got from my brother. It was left over industrial grade foam from a project he was involved with. I picked up the foam in Hunington Beach. My third EPS score came from Senergy Todd. Two longboard blanks…not sure where he got them…Todd is up near Los Angeles…
I think it’s safe to say that all my foam came from the same factory…I strongly believe that all my 2# EPS foam has met an industry standard that makes sure that every customer gets what he paid for…I’m talking about industrial grade foam that comes in block form. Need a EPS blank??? Call Ken…Swegway Composites…or Call Justin at Graphite Master