I was patching a ding the other day and left my board out in the sun so the resin would dry more quickly. I came back to see that the sun had melted the foam under the black spray-on band around the rail of the board! (FYI, the melting point of EPS foam ~ 165 F.) The rail is now about 1.5" thick and there’s a channel on the underside (pics attached). The melted section is about 22" in length and reaches 3" in from the edge of the rail.
Any ideas on how to approach the repair? I am quite new at this, so I’m sort of at a loss.
You might just go surf it first, there might some hidden ride advantage. Surfboard building has a long history of ‘‘happy accidents’’ that improved board performance. As to the fix? It looks daunting. Best advice is to avoid large areas of dark colors, and avoid prolonged sun exposure, in the future.
the glass along that rail was totally cured long-ago, and it’s the foam under the glass that melted (i am assuming). the patch i was doing and trying to speed up was on an unrelated ding on a different part of the board. does that clear it up?
I got a board back from a chum that had 2 new channels deep in the bootom. It hung up on the rail bad on one side. So I routed the giant divot out, about 1 ft square. Then cut some EPs and put that in.
Shaping it to match the board went pretty bad. I skimmed it with thickened epoxy. Sanded. Skimmed again. Sanded. Looked OK. Not any weight difference. Put some glass on with some poly resin. Somehow it found some pinholes and snuck through the epoxy… It cooked like a southern BBQ. Melted so much eps. When it cooled I sanded then finished the job. But its heavy asnsh1t now. Surfed terrible. So so bad. And it was such a good board before. Swapped it for a snowboard.
Probably a bit late for your repair, RTR, but I had a very similar rail channel on a old board. I was at a loss at to where it came from, but you’re making me wonder now.
I did similar repair to Toaster - I sanded the whole effected region, then routed out the glass and foam slightly inset from the edge of the effected area to a shallow depth. Cut a rectangular block of new foam to fit and glue in with epoxy/filler. Go thick on the filler so this glue is less dense - that way it will shape better than straight epoxy. ie, it will have properties more closely matching your foam.
The reason you’ve routed a smaller area than what you’ve sanded is because the edges of the crater that you didn’t route are the fairing/landing area for the glass you’re now going to lay over the new foam. The idea is that the new glass matches the rest of the board in thickness and stiffness. The overlap of old and new glass prevents stress risers or weak spots. There will be excess glass thickness at the outer edge of the crater. Sand this flush with the bottom. Re gloss or whatever finish as required.
Mine worked well, although I didn’t pay much attention to colour matching. I used some flour instead of Q-Cell to yellow up the repair deliberatley. I ended up with a moderately yellow board, a white region of new foam, and very yellow region of visible thickener. Oh well. A lick of paint would fix that if I was concerned.
I’m curious; What kind of foam was it. Poly?? Do you know the brand of the blank?? If you want to save it; Take a saw to it and cut that area out. Glue in a chunk of foam and reshape the rail. Otherwise; Sacrifice it to the surf gods.
If so, I haven’t actually ridden that board again since. It’s been sitting in the shed, waiting for an appropriate swell day, which frankly hasn’t happened in the last 6 months. I might take it to indo in a few weeks as a spare board. If so, I’ll report in.
