Epoxy repair, hypto krypto

[gsseirik]

Today i gave the ding another go. The foam coated with epoxy resin seemed sealed. I filled the area with q-cell mixture, and guess what: A bubble formed in a specific spot, and when it bursted I could see down to the foam. Took the board out in the sun just to see what would happen. In that exact spot a new bubble emerged and burst over and over again. Took the board down in the basement again and tried to work it out with a squeege. I could feel the mixture starting to get less moveable. I hope the solution is to wait until it gets hard enough so that its hard for the air or gas to push its way out..

Just as an experiment I used that same mixture on some exposed foam on my wife's PU polyester board...Not a single bubble, and a perfect seal.

This is how my board looks after working with it during curing:

Seems sealed.. Sorry for the nagging guys, but im starting to get desperate

[gsseirik]

Today I continued with the dingrepair-project. Got hold of some real E-glass for surfboards, and that was musch easier to work with. Laid a second layer on the dings that only had 1 layer, and laid a "hot" coat on one of the dings.

Not sure if this is relevant for this forum

[saltydog]

You may get be mixing the q-cell slurry too vigorously and end up beating in air bubbles. I get the bubbles from PU board repair as well. I usually refill the bubbles with thinner q-cell mix and really stuff that in the air pockets with a piece of wire. Straightened paper clips work too. It looks like your repair is coming along nicely, though.

[gsseirik]

Thanks saltydog! I tried everything with those bubbles..But the combination that worked this time was to preheat the board in the sun (so that the EPS would start to outgas) then bring the board in a cooler enviroment while filling the ding (so that the EPS would start to suck air/filler instead). When the filler started to be less moveable the bubbling stopped. Sealing the cavity with a thin layer was also a good idea, but a tiny spot wasnt completely sealed after all.

Do you also get airbubbles or canals that go all the way down to the foam on PU's?

[saltydog]

My bubbles were not coming from the bottom of the cavity unlike yours, so it does seem like you've got some outgassing from EPS foam for having the air gaps. Making use of the temp change that affects the volume of the gas is an excellent idea. I'll remember that in addition to Waikikikichan's suggestion of coating with some resin the next time I need to work with epoxy boards.

[gsseirik]

Yeah. Another trick I found useful to locate the canals was to turn of the lights, and then shine a flaslight under the surfboard, and you could clearly see the canals which outgased lighting up. Enclosed airbubbles is easier to fill. But to fill the canals was like trying to plug a tire-hole at the same time as you inflate the tire. Heres a pick of the last coat, prior to the last sanding:

As you can see the q-cell area is very contaminated and discolored from various sanding papers and a large amount of attempts. But now its finally water-proof, and I can finally surf it again. Will experiment with different fin setups like Waikikikichan suggested in another thread.