I had a fiberglass airplane painted in an automotive paint shop and it came out pretty good...then the airplane sat outside in the Arizona heat and now in some areas the paint is developing some blisters. My guess is that the paint shop did not wipe down the sanding dust from the surface sufficiently enough and when the airplane sat outside in the heat a small bubble began to develop under the paint and the paint coating kept lifting off the fiberglass surface and the bubble grew so now I have a couple of fairly large air bubble blisters on my wing (see picture). Naturally I need to use a pin and prick a hole in the blister to pop the bubble but then what is the next? Is there some kind of adhesive spray into the hole and then push down on the bump to bleed out the air and get the adhesive to stick the paint back down onto the surface? Any advice would be greatly appreciated! Thanks!!!
Was the glass raw or previously painted? If raw I would suspect resin solvents gassing off in the heat and "inflating" the paint coating. Paint process undercoats top coated before they flashed off solvents could also be a source of solvent. Paint doesn't usually blister from heat alone. It's more likely to shrink with heat. Paint usually doesn't blister from poor adhesion. It's more apt to peel. I would wait for a while to see if more blisters appear. The blister is stretched paint film and difficult if not impossible to reverse.
I don't think that there is any magic bandaid on that one. I'd say that John Warden pretty well gave the righr explanation though.
I had that happen to a fiberglass topper that was left outside upside down and filled with water. Somehow the water found it's way through the fiberglass and blistered the paint.
https://www.jamestowndistributors.c...tle=West+System+-+Adding+Fillers+&+Additives+ I use the silica fillers and resin from the West System, dig out the areas and mix up the fillers in the form that you need(thick or thin) sand down and your good to go!! Pete
I used a pin and stuck a hole in the paint bubble so there is no longer any pressure inside the bubble. I guess the question is...what should I do now??? Use a heat gun and see if I can press the bubble back down??? Use some kind af adhesive to press and hold the bubble down??? THANKS again for your advice!!!
Did you ask the guys that painted it? You can inject glue just like you would insulin. Will it work??? What you got to loose ?
I’ve had to deal with osmotic blisters on fiberglass sailboats. The blisters are a result of contamination within the layers of fiberglass and the blister start around dust or other particles absorbing water. Some of the solvents and resins used in construction are water soluble and pull water into the blister. The liquid inside the blister usually has a very foul smell. The only way to fix properly is to grind out the blister to solid substrate let the area dry completely. This can be helped with alcohol or other solvent like acetone. You will they have to do a fiberglass repair with glass and resin sand and repaint. Some of the resins used in construction are more subject to blisters usually the polyester resins. Vinylester is now used on boats and can be used for repairs because of its resistance to water. The bad news is once the blisters start to form there will no doubt be others in other areas.
I had a smaller bubble, popped it, heated it so the paint was flexible, used a insulin needle from the pharmacy to inject superglue, squished it around as I pressed the bubble down, glued my fingers together but the repair is still holding. 20 footer on my olds.
Bandit Billy did exactly what I was thinking. Sounds like the best way to repair your issue to me. Sent from my LM-Q720 using The H.A.M.B. mobile app
Could be more serious, like an air bubble in the fiberglass itself. Air gets heated up and expands....paint bubble! Grind, re-fill, and repaint is the only solution to this.
Just my opinion but because this is an aircraft it warrants further investigation. The blisters could be a sign of delamination. Not an expert but been around general aviation enough to know the fiberglass skin is a big part of the structural integrity of the air frame.
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