I just finished an eps-epoxy short board. I accidentally sanded through my fill coat in a few spots and was wondering if a) this could be fixed with a little rattle can clear coat instead of filling and then sanding again, or b) didnt need a fix at all and could be ridden as is. Other than acouple burn throughs I am pretty happy with my sanding job so im not sure that I want to clear coat the whole thing. I was thinking just tape off the spots that needed it and spray them. If this is a bad idea tell me now please so I dont ruin all my hard work.
If your gonna spray it and wait for it to dry anyway, you might as well spray the whole thing. If you fill the spots with resin and sand them down I think it’d be your best bet
Whenever I “fill the spots with resin and sand them down” I always end up just exposing more weave around the borders of where I just spot-coated. Something I’m gonna try on my current board is to spot-coat the burnthroughs with rattle-can clear (matte). Lightly sand the edges, then coat the whole board with Behr acrylic sealer (which I always do anyway).
Rattle can clear won’t hide places where you can see the weave. Sometimes resin won’t help either, depends on the kind of glass you use.
I have a heavy tight weave glass and a burn through usually stays visible. Surfboard glass is more forgiving, but I got this crappy glass so cheap. I learned why later. Too bad it was a lot of glass, I still have so much left.
That’s one thing I’ve thought about, but haven’t done. What I do now is to fold/roll the glass up from rail to center, I’ll do half then fold it again to get it as close to the center. I’ll pour some resin on the glass and squeegee all over then toward the opposite side, I’ll pull the first fold back then do the same for the second piece. The goal is to get all the glass and foam wet. Then I do the same for the opposite side. You need to mess with the glass a bit to get it layed out smooth, then pour the resin out on the top side and work it in. I’ve found that I may need to wet the rails again even though the glass was saturated to get a good lap. I use a 2" chip brush for that. A lot of hassle and it can be a problem with the cure times of resin here in Hawaii. I use slow epoxy, but all the wetting of folds takes time. Sometimes I use a second batch of resin to get the laps wetted out real good.
I just did a 9’ 7" poly blank, and I used poly resin with less than 10% catalyst. I made the mistake of trying to do a fancy splash design with 3 colors by throwing streaks all over the board. Took some time to do, then I noticed that the resin wasn’t going through to the foam. I had to pull up the glass to get resin under the unsaturated glass. The resin was begining to harden before I had both sides lapped, and all the work to get it into the glass ended up making the end product kind of muddy.
This glass has a tight weave compared to surfboard glass. I’m thinking this stuff is probably 10oz. I just added another lam over a cloth inlay and I used 2 layers of hexel 4 oz. I layed out 6 oz first, but I noticed that I could get 2 layers on a smaller board, so I saved it. The 6 oz was much lighter and the weave was much looser. Funny, even though the weave is tight, it will shed strings very easily.
In the past I’ve rolled up the glass from nose to tail stopping at the middle, then I’ll pour out resin on the blank and get it all wet, then I roll the glass back down and do the other side. I still had issues smoothing out the glass, so I tried the side to middle folding and wetting. It seems to work better. If I did a clear or solid color I can get the lam done before it starts to gel. I’ll be happy when I get through this roll. It didn’t bother me as much before because I was making the blanks from rockered slices of EPS or XPS foam and the blanks were costing me about $5 - $10 to make. I’ll probably use up some to make fin panels. I’ve been making the fins for my boards recently, and I think I’m getting that dialed in now. I used to be able to find reasonably priced sheets of G10, but it’s getting more expensive and a lot of places on eBay won’t ship to Hawaii.
If you use quality components you’ll get a much better end product and it will be so much easier and faster. I’m learning a lot of things most people will never want to bother with, or have to deal with. I’m going to know all the don’t do this stuff or how the fix this mess before long.
Mahalo Harry, my experiences with some 7 or 8oz ebay ‘mystery’ cloth are about the same. My wet-out table was the garage floor covered with Masonite and poly sheeting. It would have gone better on a shorter board or with some help, sort of ran out of time working with fast epoxy on a 12’-6" x 31" SUP by myself. I also neglected to clean the PCV pipe that I used to transfer the cloth from floor to the board so I got the ink from the pipe on the board. I also trimmed the cloth first, thinking I’d save epoxy. Next time I will allow a couple more inches width so I don’t have to center it as well either.
It depends on how severe the burn through is if a clear spray will help. Test it and see what happens. If it works OK for you, I recommend Rustoleum 2x clear. It’s very durable and I use gloss then a brown scotchbrite for a matte finish. The gloss seems to have more even coverage and you can cut it in easier. Use 2 coats. If you need more to cut in the edges than the scotchbrite, use 600 grit. Just make sure it’s really dry. If you have a hook & loop pad on an orbital sander, just stick the scotchbrite right on that.
If the rattle can doesn’t work, lighty sand the burn through to expose some cloth and apply some xylene with a Q-tip and see what happens. If it goes away, do it again then immediately put epoxy over it (fastest cure). Maybe do another coat of epoxy and hand sand to cut in the edges. Xylene is nasty stuff so take the necessary precautions. Home Depot has both the xylene and the Rustoleum 2x clear.
The burn through me are very minor so I think the clear coat will work. Just a few spots on the rails. When I ground down the free lap on the bottom I hit a few spots that I didn’t want to with the grinder so I added more cloth there to beef it up. And then when I fill coated the bottom I didn’t blend it in very well so I burned through the edges on my final sanding.
I will put the gloss coat on and sand it like u said.
As Pete says be very careful with the xylene. It will dissolve EPS faster than you can say “Oh shit!” Acetone will also melt EPS.
If there is a possibility that you have a pin hole, you may not want to use xylene. Or, and I haven’t tried it, but maybe if the board is upside down and you put a little xylene on it won’t go into the foam when you do the test. I’ll have to try that on my next burn throughs.
Wear a good respirator, and gloves. I usually use 2 pairs of gloves, nitrile gloves and then a heavier longer glove over that.
I use xylene to thin epoxy and to clean off probox install guides after I use them. It cleans through the spray glue really well. Then I use Denatured Alchohol, then water to wash them.
So far I’m pretty impressed with the Rustoleum 2x Clear. First coat hid the weave, 2nd coat filled it. Gonna scotch brite it with maroon THEN seal the board with Behr Sealer.
I use the Rustoleum 2X also. good stuff. Other rattle can stuff seems too thin and doesn’t cover well. You will get good weave coverage with the Behr stuff. But only for minor lightly sanded weave. I prefer the Behr method because I don’t like spraying and all the fumes. I can put a couple of coats of Behr on in an hour and be done with it.
Xelene is nasty stuff. Bet very careful. If you get it on you, don’t plan to have children.
Dang, JRandy. You were just asking for a headache. I use a wet out table method that I adopted from “Dwight” who posts here. Very tidy method. Also, I built a plywood table 8X2.5 and put it on a couple of plastic saw horses so I’m not crawling on the floor. Mostly I do vac bag with the wet out table and therefore use RR extra slow resin. So I have plenty of time. And as you learned don’t trim the cloth too much before laying it on. Get a jug of vinegar and just clean your epoxy wet siscors afterward.
I use a pair of short scissors to get to all the strings. I clean them off with Denatured Alcohol. A wet out table would probably help to keep optimum resin/cloth ratios.
I have a couple of cans of the 2x waiting to be used. I’ve tried so many brands, sometimes I’ll find something that seems good then the next can doesn’t seem to be as good as I thought. Hate when it comes out splotchy, and I’ve had a few brands do that to me. Got something from the NAPA store once that I really liked, but couldn’t seem to find it again. Threw the used can away long ago, and have forgotten the brand. I figure a rattle can clear spray for car finishes should be good.