Hello,
I am new to the swaylocKS community, though traversed the archives quite a bit. I am working on a board using closed-cell Divinycell foam, H-60 (4 pound density), and was wondering if anyone had any luck with the stuff? I have gotten the shape down, did a three-ply layup (3/4 inch sheets) to get the rocker and general thickness, and shaped, shaped, shaped…but the weight still seems to be a tad heavy. I have seen plenty of boards using a closed-cell outer layer but not a ton throughout, is this a lost cause?
Thanks
MakaiProject- Welcome to “Sways”. After reading your post the question comes up as to why you made the board entirely from divinicell? Were you looking for some kind of “bulletproof” “tank” type board?
Divinicell is a pvc foam typically used as part of a composite sandwich construction with a lightweight EPS core. It’s meant to add strength to a light weak core foam like EPS. Besides being extra heavy & stiff, the stuff is very expensive. A compsand is the way to go. That being said, why do you ask if it’s a lost cause? Have you surfed it yet? If it surfs well,enjoy it till you shape your next one. If not, lesson learned & move on to the next board.
Divinicell over EPS is basically how surftech boards were made. 1/8" glassed on both sides over EPS. Solid divinicell would be way expensive overkill.
HI Parthenon surfer,
Thanks for the prompt reply. I went with divinycell because I am currently working on a large boat and essentially have an extra case of the stuff so thought what the hell. I just glassed the board with 6o s-glass and epoxy, have a bit of sanding to do and will get it wet soon, hopefully this weekend. Was thinking of making a second board - current board is a 5’9" fish - and didn’t want to burn through another $100 of material if there was a better layup schedule. Might try a combo for the next to shave a few pounds
Maybe you could treat it like it was balsa wood and do a chambered blank? This might get the weight down. There are two types of hollow wood board construction you could do. Search the forum for them. If the d-cell is essentially free it seems like a no-brainer to use it. I think it’s an opportunity to do something cool. D-cell does turn color when exposed to UV light so you may want to glass with pigment. It is also pretty flexible compared to wood so you may need to bump up the thickness or add a stringer
yeah chambering came to my mind as well. also you might want to try strip(s) as stringer(s) with lighter density foam. or make wakeboard/kiteboard or skimboard.
I like the chambered idea; just finished up a hollow wooden sup, though the thing came out like a log. For the d-cell board I’m finishing now I laminated 3 sheets of 3/4 to build the basic rocker and thickness; it’s pretty stiff, though time will tell once I get it wet. One of the main issues I had with the h60 was it soaked up resin like a sponge, way more than the higher density - i’m lucky to get a 50/50 glass:epoxy ratio with this stuff, i normally get a 65/35. I was thinking of doing a polystyrene/d-cell for the next board off the rack, maybe beef up the rails with a higher density d-cell to accommodate for the poor shape-ability of the poly.
There are two ways to keep d cell from soaking epoxy.
One way is to seal the blank with a microballoon slurry.
The other way is to use gravity. Wet the cloth on a wet out table. Drape the wet cloth over the blank. Wrap it in plastic, or peel ply. Put it in a vacuum bag, and turn it over so the cloth is on the bottom. Gravity will keep the epoxy in the cloth, and out of the blank.
Where are you located? Are you on Oahu? I’m on Oahu, Kaimuki side. I’ve been thinking about getting some HD foam from Fiberglass Hawaii.
If you want to do a trade of Divinycell for an EPS blank, I have several stringered 1 lb EPS blanks I got from Pacific Allied Products. These are light and are great with a veneer on the deck. I usually use 1/16" or 1/8" balsa, but I’ve made a couple boards with just the blank and 3 layers of glass. I would not add 3/4" of divinycell, maybe 1/8".
I have one 6-4 and a couple 9-4 rectangular blocks with rockers cut and stringers inserted.
I was told to do a seal coat too. Divinycell sucks up the resin.