I am having the same issue on my 66. This will be the fourth time for the bubbles on the nose...not on the hood but the nose piece. A real bummer since the rest of the car is flawless.

Not sure how to add a pix to this post to show you.

 

Sounds to me that there was some sort of contamination that got on the glass at some point in it's life, maybe even from the factory.Could beoil, siliconeor something similar. It will soak into the glass and rasie to the top(or create fumes)when exposed to heat. Hood insulation may help, but the heat itself is prolly not the actual cause, just a contributing factor. Not sure what a good fix for this would be other than to strip the paint and throughly degrease the area with acetone or some other fairly aggressive degreaser.don't leave iton the glass to longthough.

 

ive got a few. i think mine are coming from a combination of oil being shoot up on to the under side of the hood(pan gasket leak) and heat. the reason i say this is becasue the bubbles are on the same spot as the oil was when i cleaned it.i dont have an insulator by the way im planning on getting one as soon as the leak is fixed.

 

Happened to me too. Hood has bubbles on the middle passenger side. Will be putting insulation underneath. My only concern with that is the insulation catching fire. I did get the foil insulation so hopefully that will reflect most of the heat.

 

bumping...

 

sounds like to much flex in the paint and not enough hardener, tell the person who painted it he used the wrong mix for a fiberglass car , most people dont pain fiberglass cars often so they dont understand how it works! get the best advise you can get is from a person who paints boats

 

Might try putting on new gel coat next time you paint.

 

Clean the under side of the hood or effected area with MEK(methylethyl keatone) and paint it with a polyester based paint or gelcoat to seal it. Then replace your insulation.

 

Even if the problem isn't with the primer, the right primer coat can help in alot of cases. With any primer, make sure it is FULLY cured before you paint over it. A little extra time in the booth can do wonders. Some of the resin and catalyst (hardener) can be left unreacted in the paint, and "fume off" as much as a year or more later. I too like the polyester resin high build primers on glass, and have always done a double bake (once after spray, once after sand and wipe).

You can also have leftover resin and hardener in the fiberglass itself or gelcoat, which can seep *years* and even decades after the glass and gelcoat are laid out. Bad mixtures can have "blisters" from heat or excessive moisture triggers over time. Nothing you can do about it except pop them, dig a bit, sand them down, seal them, gel or bondo over them, and pray. A good cleaning, and a good sealer can keep this from showing up most of the time, but...

bill.