I tend to order the USB “super fused” or the Marko “pressured molded” blanks in 2lb density for my eps shapes. However, I recently built a 10-0 LB using the USB slab-cut “White Hot” 2lb eps. After surfing it almost daily for 2 weeks, I cleaned off the wax and found multiple (as in more than I could count) heel dents on the deck (glassed 4+4+4 s-cloth deck, 4+4 s-cloth bottom). I’ve never had this problem before, and I was wondering what others have experienced with the USB Slab-cuts.
Slab cut blanks for anything other than SUP’s can be chancy if you are not cutting it yourself. The Billet that boards are cut from is always denser on the top and bottom of the billet so boards cut nearer the top are better fused than boards cut from the middle of the billet. The smaller the billet the better the fusion from cuts done in the middle. If I were doing LB’s from EPS I would always try to use Marko as the single molded blank will always be fused almost all the way into the middle of the blank. 2.5 lb. EPS is always the go-to density if you are trying to make a bullet proof longboard. Your glass schedule is ok for a longboard in EPS/epoxy so I would think it’s more a problem with the density/fusion of the foam. SUP’s normally have a heavier glassing schedule than what you stated. I do make a few SUP’s only for friends & family and have run into problems with unfused/lightly fused bead. I could go into this with more detail if you want me to. I have 13 years past experience of molding EPS and the plant I managed was a direct competitor of Marko so I am really familiar with the material. I still don’t understand why my old company didn’t go into blank making when Clark went out of business, but I had left by then, so… just my 2c!
Thanks for the informative reply, Surfteach. My glasser does a substantial number of SUPs which are mostly 1.7# (I’ve scrubbed more than I’d like to admit). I was hoping that 2.0# would not require the expense of carbon fiber and/or VectorNet. And, since I wanted a 10-0 and USB and Marko only have 9-8 and 9-6 blanks respectively, I figured the slab-cut was my answer. Guess not…At only 17.5lbs, the board has turned out to be a small-wave-catching machine, and although too light to be a good noserider, it feels more like a 9-0 under foot. I’ll have to try the USB 9-8 Superfused as a compromise.
I don’t know where you are at but here on the west coast (US) 2lb. usually requires 6oz. cloth for a strong board. The problem is that much cloth & resin tend to deaden the board and other than noseriders, most longboard surfers prefer a board with a bit of spring which is why PU is the prefered foam. Marko does make a good 9.8 blank that is well fused, I don’t know if you can order a heavier density where you are. If you are going with 2 lb, there are lots of glassing tricks that will make it a bit more bullet proof on the deck with your 4 oz. schedule. Also, you can always add a deck patch! I would stay away from carbon & net for a general purpose longboard, just not worth the cost and you will get dents anyway. Hope this helps, just my 2c…
I chose the 4+4+4 deck specifically to avoid that bullet-proof-but-dead feel. Maybe “red” denisity PU with deck patch is a better way to go to get that combination of durability, light-but-not-too-light feel in a 10-0 LB. I’m not a “heavy log” LBer. and prefer weight to be under 20lb. To many trips down the path to PV Cove in the late 60s with 35lb boards. BTW, Ventura County…
This really shold be over on General Discussion. For one thing you would get more response over there. I don’t see how this fits Industry Talk. You guys have been around enought to know better. Not starting a war, just pointing out the obvious.