Doing second epoxy hotcoat due to air bubbles, burn throughs. Can I sand further down and fully expose fiberglass?

General Discussion
1

Almost done my first board. Have been reading Swaylocks religiously but still messed up my freelaps for lam coat. The bottom is pretty flawless, but the top had a bunch of fiberglass strings and bumps that I didn’t sand down fully (should have basted, I realize now). Hotcoat went on fine and seemed alright, but when I started to sand it down I got some immediate burn throughs on the bumps.

I was hoping to not do another coat (no gloss coat planned either) but I believe I need to do it.

What I’ve done now is sanded down the entire deck to be pretty much perfectly flat / level now. No bumps, etc.

The issue, the thing I’m wondering about, is that while sanding I can see the fiberglass weave, but when I clear away the dust, while not exposed (as in, I can’t touch and feel fiberglass), it is visible underneath the thin layer of epoxy from the lam / hot coat.

See photos for reference.

Full quality imgur album here: https://imgur.com/a/StFIx5n

Here is one of the photos:

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My question is: should I continue sanding down and fully expose these fiberglass parts? Would that help improve the appearance?

My thought process is: if I sand down further, and fiberglass is exposed (I don’t know if it really would be exposed or not though), the next coat of resin can get in further and saturate the glass / area better.

 

The board looks good other than the rails / nose / tail (hah). It’s a shame my glassing job turned out bad.

Is there a way to salvage this and fix up these problem areas? Will a second hot coat help cover this up enough?

2

assuming polyeurathane resin since you are using words like “hot coat”  Sand pock marks down as much as possible. Blow out  pock marks of sanding dust. Tapin off rail do another coat of a sandable resin on each side. 

Epoxy resin of a quality surfboard type would be the best solution even at this poingt of the build.

Post pics when done

3

Hey!

Thanks for the reply.

Sorry, should have mentioned it is epoxy. I used term hot coat as that is how the Greenlight guide explains it, even though they use epoxy as well.

Got it, I’m going to sand it down a bit more and then throw on another coat

4

I just did nearly the exact same thing. Get the board as perfectly smooth as you can now with 120 grit or so, fix all the bumps and low spots as was said above. CLEAN the surface with alcohol (some seem to prefer just water) and lay another coat of epoxy once it’s exactly how you want it. You should then only have to minimally sand the last coat as it should come out almost perfectly smooth. Hand sand nose/tail/rails/concaves (especially the expoxy bead around the rails (there has to be an easier way!). I power sanded the flats of the final coat starting with 220 and quickly moved to wet 320/400 and it worked well. If you want a matte finish a maroon scotch-bright pad works well on the nose/tail/rails.

5

Lovely.

Second hot coat just hardened. Board is looking suuuuper level now (as it should have a few coats ago, hah).

The white spots / burnthroughs are still visible, but I’m thinking when I sand and finish with that maroon pad it will look a bit better than right now just full gloss.

Thanks a bunch for the help, everyone!

 

Excited to get this out in the water, and then start board #2 :slight_smile:

6

So I’ve done one board, there are many others on here you want to listen to before me, but I think I see bubbles in the lam (under the fiberglass). I believe any exposed fiberglass should go clear when you put another epoxy coat on, which it probably did with your latest coat. My guess is the remaining white spots are either bubbles or a spot where you sanded down to the foam. It sounds like some folks fix bubbles by filling them with resin using syringes/needles. I had one spot on my board where I sanded through the glass to the foam and didn’t realize until after my final coat. When I pressed on it it was really soft. So i cut the resin out with a razor blade, and put a fiberglass patch over it, then sanded and put a final coat over it.