I’m working on my first surfboard glass job. The board is my dads old 1960’s longboard. It was all beat up and delaminated. I removed all the fiberglass and moldy foam. Replaced the bad foam with Totalboat 2 part boat foam and sanded it smooth. Then I used patch & paint to get rid of any small divets. Then I painted the board with a thin layer of acrylic house paint. After watching many videos and reading as much as I could I laminated the bottom of the board. It went fairly well but I ended up with a bunch of bubbles. I sanded them out and patched them with glass. I thought maybe I was leaving dry spots. So for the deck I made sure to dab extra resin on the bubbles when they popped up. That didn’t help. No amount of babysitting got the bubbles out.
Actually that looks like a Cloth issue. Contamination. If they are bubbles they will be slightly raised due to trapped air or lack of adhesion. If you or someone else spilled/spattered something on the cloth before lamination; Those spots may be due to the fact that they are sealed and won’t take resin. OR Contamination on the surface of the board under glass.
I made sure to lightly sand the board and used an air compressor to blow it off right before laying the cloth down. The cloth cam right out of a sealed bag from the supply store and onto the board. As I was moving the resin across the board and soaking the cloth these bubbles were appearing. Some of them I could make disappear by working the air out as I wrapped the rails. However, many could not be manipulated. This problem happened on both the bottom and the deck of the board.
I did “pull the resin out while pushing the cloth down”. I ended up with bubbles. The resin pools you see we’re left over after I tried to dab the bubbles out with more resin.
Taking cloth out of plastic is no assurance that it wasn’t contaminated during the manufacture process. I have found defects, pulled strings and stains on brand new rolls. Brand new rollls wrapped in plastic and boxed by two out of three of the top manufacturers of Surfboard cloth. It happens. Hell! You could have contaminated the blank when you blew it off. Oil or water from your compressor would do it. If they are bubbles yo should be able to razor cut them and patch.
Well I ended up sanding out the bubbles. It was a good bit of work and always mentally difficult to backtrack. I sanded through both layers of fiberglass wherever there was a big bubble. Then I mixed up some resin and hardner with micospheres into a thicker paste and filled in the spots where I sanded through the glass. Then sanded everything smooth and painted the board again covering up the white microsphere areas. This time I lightly sanded my paint job and then brushed off the dust with a clean brush. NO AIR COMPRESSOR! Then I glassed over everything with 4oz cloth and didn’t see a single bubble.
