Ah EPS, pretty much the red-headed step brother to PU foam. No it’s not new. Post WW2 technology. Most people when talking about “epoxy surfboards” assume it’s the foam. No, it’s the resin. I actually love the resin. Makes a really strong shell on PU. The problem with this foam that I have is beyond the production, the real issue is the “S” in EPS. Styrene. Read a can of Styrene. A “known” carcinogen. Yes, it causes cancer. Ever wonder why McDonald’s coffee switched from Styrofoam cups to paper overnight, real quiet like? That’s because, when heated. Styrofoam releases Styrene when heated. This info really freaks out my friends with shaping machines, who heat up the foam when machining. The other issue is trash. When the “blank” thing happened, because of its availability, EPS became the most abundant foam. Because most was solid billet foam blocks, the excess foam became waste. Lots of it. With all the shaping machines around me, I saw every trash day become a snow storm of EPS blowing around everywhere. Thankfully, some of the molded EPS has become more popular. (less waste). I’m trying not to hate too much on this foam. I guess it has its place in the marketplace. I do love the RR resin, its a good, well developed product. The foam however does kinda trouble me.
Yeah Greg you are correct. That purple board melted with the heat. My ding guy sees this all the time. It happens on all the dark areas when left in the sun. Dark colors are not good on EPS. However it does cover all the flaws in the production of the board. ( Especially the China boards).
…the PU shrink with the conditions you describe and there are no delamination so Im not totally sure about your point.
As many here noted, I paint lots of board with deep dark colors; never had one with a delamination due to Sun exposure; I bet if I do that on PS I ll have delaminations; but sometimes is a bonding issue, at least with resins that are not specifically oriented, like the Loehr´s
Delam around the fins are from the bonehead running the fins into the sand. Possible the blue delam was from the paint but I’d wager melted foam. McD’s coffee is 165F. EPS melts at 180F. Inside a car in FL can top 200F. But cut it open and find out. Reverb, being from FL we just didn’t make dark colored boards even in the PU days. Just too hot there. CA boys would send these things out and you could smell them cooking on the beach. They’d shrink and have the coolest concaves.
Barry, Polyester resin that we use contains 35% styrene monomer, and surfacing agent is over 90%, styrene monomer is a known carcinogen, so talking about the S in EPS, is really more BS, and ignorance than anything else. Oh, you do great work, but I don’t think organic chemistry or plastic formulation are your strengths.
Now I agree with you pretty much on everything else; but this place is so boring because most of the people here don’t know what they are talking about, at least you can back it up with clean boardwork.
This place is getting less “boring” by the minute.
Question to all:
Why is it that Buffo Hydroflex Supercharger boards are built with eps and are meant to be pumped up with air using a hand pump, and here we’re worrying about venting an eps board to stop it from delaminating.
Someone’s doing something right and some others maybe not ?
Plenty of 1 lb (and also hollow) black CF SUP’s around that don’t delaminate. They get hotter than light colors, and so use two vents to handle the airflow. Lighter colors can help with solar loading, but unless it’s reflective there’s no affect when in a hot car or garage (radiation heat transfer). Colors are a big marketing requirement, and you won’t be in business very long just selling plain white. Really no board - poly or eps- should be left in the hot sun. Melted wax, color fading, yellowing, + all the other major bad stuff is going to happen. Most of us around here are conscious of this maybe since we know the labor that goes into making a board.
On melted eps, well I’ve seen more as a result of finbox installations than being left in the sun. However, locally here we have some morons that leave SUP’s on their yachts in the sun for weeks. Not just a couple either, and yes several inches of foam is melted away under the glass.
Ive found that vents are not needed on light eps , if the skin is constructed strong enough to ecxeed the pressure exerted when the core gets hot…simple really…had a delam 20 yrs ago, and none since…a lightweight glass job , on light eps is just asking for trouble , and should be vented…if the skin is bonded properly , it wont delam…
I repair about 10 boards with massive delam like John picture (and more). Most of them where same built: shit eps with thick lam and dark paint left in sun or car. For same problem i repair 2 boards i made, a firewire rapidfire and some imported well known labels.
What i see is that it’s eps that destroy not the skin that delam like PE on PU, EPS beads left attach to the free skin. On boards that use better eps, denser or with better fusion, this problem seems to happen after the board work hard, when the core experiment some strong shear. I found that let resin drain a bit in eps is really efficient against those problems.
Thanks everybody! As usual, there’s no shortage of information to be gleaned from swaylocks. I think for now what I’ll do is put vents in the boards I make for friends, and leave them out of my personal boards, and see how it goes from there. Thanks again!
I’ve made a few boards using eps foam & ran into the same problem requiring a vent plug. First, my thoughts- any increased temperature changes will cause expansion, pretty much like blowing air into a balloon. If there are any pinholes,fractures, or the like, the air will escape through these spots. On entering the water, the air will now contract, pulling water into the board, where it will stay, probably forever, & slowly get heavier as more water accumulates over time. A membrane type vent plug should solve the problem- The prices run from $11- $27, depending on the manufacture- I’ve put together a couple using a piece of the breathable/waterproof fabric with a fiberglass cover over it for protection. It doesn’t have to be very big- a quarter inch hole in the deck, with the fabfic over it with either silicone or epoxy, & the overlapping cover with a couple of small holes drilled in it & resined around the edges does the job. A little testing will show the best methods.
I am really glad to see this topic pop back up. Though not much new seems to have happened. I am making balsa composite boards with a 1# eps core. I have made my own gore Tex vents following in the footsteps of Speedneedle . They seem to work ok. But my dilemma is that I live in Oregon. Cold , wet Oregon. I can probably get away with not venting here. But I occassionally do travel to warmer climes. I often wonder if vents are really necessary with my type of construction anyway. Just have an aversion to punching holes in a perfectly good board and leaving them open except for a tiny piece of fabric.
Any other composite guys out there have experience they can share?
I’m using Gore Tex as my vent fabric. It works really well. My worry is that if I don’t vent eventually all the expanding and contracting will cause the core to begin degrading. If my beads aren’t stuck together good then no matter how strong my skin is the board will fail.
I’m using Gore Tex as my vent fabric. It works really well. My worry is that if I don’t vent eventually all the expanding and contracting will cause the core to begin degrading. If my beads aren’t stuck together good then no matter how strong my skin is the board will fail.
