Split my rail with my leash. Got it filled with loads of qcell/casting resin since the pour foam was crazy expensive. Gonna color match it and then glass over. I only shape with polyester. I got a little casting epoxy resin pack. Now it sanded down alright but idk if it’ll work well with actually laminating cloth over the rail. Should a get epoxy casting resin and sanding resin or will the casting one work fine for the small patch since im probably not shaping or getting another epoxy board. Will it blend like polyester sanding resin does?
I have never used casting resin on a surfboard.
Since you are not heading towards EPS w/epoxy surfboards, a big buy-in for surfboard epoxy resin does not make sense. Also, too big of a repair with epoxy can lead to an exothermal runaway and melting the EPS foam around the repair/finbox/etc.
Is the mixed casting epoxy thick or thin? Maybe try wetting out a small piece of cloth off to the side and figure out how long it takes to kick and to cure before trying it on the board.
Some of the less expensive epoxies yellow rapidly in sunlight.
yea its pretty thin. It’s for sures will wet out the cloth fine. I just was wondering about blending it with around it. I know pu sanding resin with little bit of sanding blends really easily. It’ll be a trial and error then. Easy enough too sand away if it doesn’t work.
The exothermal thing is kinda cool too know. I was wondering about how epoxy works with that. I know if I mix in extra catalyst with the pu it starts smoking and defiantly will melt a fin box. I mixed in extra part b for the epoxy since it was took forever too go off and no steaming. Kinda cool how the pungent odor of pu wasn’t there either.
Epoxy should be mixed in the ratio (volume or weight) established by the manufacturer within their recommended application temperature range. Adding extra part B does not really make it go faster, it just weakens the final product with extra unreacted components. Real surfboard epoxies often have much better (quicker) cure times versus general purpose epoxy.
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huh that’s also very good too know. I really just assumed it was like pu but lighter and stronger.
Why do you even want to use casting resin on a surfboard? Live on a desert island or something? If you have used Poly, why not just fill it with Poly and Qcell and put a piece of cloth over it? I guess I’m missing something.
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Probably en eps foam board. If you have already do the fill with epoxy qcell, sand to initial shape, board seal, you can finish with polyester.
Casting epoxy is a long set time fluid epoxy so low exothermic temp that allow to cast without foaming or take fire. If it is a hard set one you can lam with it is but take really long to cure.
Some epoxy casting resin are make to cured flexible.
As Lemat says, the advantage of casting resin is low exothermic response. Can’t make molded epoxy objects if they go up in flames while curing.
So, epoxy casting resin “might” have an upside for filling without exotherm (especially when mixed with qcell).
OR; Epoxy and Qcell covered with Epoxy and a piece of cloth.
Might be nice not too have to worry about melting foam with a fin box/plug installation.
My only experience with casting resin was Polyester. I know that Resin Research makes an Epoxy resin suitable for casting. My use of casting resin was not related to surfboards. I found it to be a bit brittle. When I glass with Epoxy I use Resin Research 2000/2100 Fast. I don’t usually have a problem with Exotherm on fin boxes. But if I thought I might have a problem I would just set the boxes and leash plug separately with 2000/2100 “Slow”. I always have a half gallon sitting around the shop.
A quart of laminating epoxy resin was like 90 Bucks and I only needed enough too laminate the one boards rail. It’s my only epoxy board so didn’t wanna splurge on somthing I’ll never use the rest of. The casting resin was like 15 bucks from the art store. Worked out in the end. “Poly melts epoxy foam ive heard”
Poly melt eps foam, poly don’t melt epoxy resin. So if you fill and well seal eps with epoxy resin then you can laminate with poly over. If your epoxy casting resin set hard no problems lam with it only longer to take.