Paint Bubbling : WHY?!?!?!

Christo Fett

Active Hunter
Well my FG bucket is almost ready for paint and I hit it with some primer and the primer is bubbling up. The texture looks almost like tree bark. I sanded it down cleaned the helmet with rubbing alcohol hit it again with some primer and it did the same thing. Can anyone tell me why and if there is something that I can clean my helmet with so this won't happen?
 

judz dwedd

Well-Known Hunter
If it's a gelcoated helmet, try washing it down with acetone. Some people, (most probably) cast helmets from a silicone mold. Silicone molds tend to leave a silicone oil residue on parts cast from them. Also, polyester based resins have a sticky surface when cast from silicone molds. This also is removed with the acetone.

If it's a urethane resin helmet, DO NOT use acetone on it. Acetone will damage urethane resin.
 

Jun Garros Fett

Active Hunter
Possibly bad can of primer?

I havn't painted a helmet yet but have built models for many years. It's possible some of the release agent used to get it out of the mold might still be on the helmet.
I have used comet cleanser and an old toothbrush in warm water to remove this stuff from resin parts. Have heard wesly's bleach white used on white wall tires works well too. Not sure what it would do to the fiberglass. I would recomend if you try it to test it first.
The comet shouldn't have any effect on the FG.


Just my 2 cents.
Hope it helps.

 

judz dwedd

Well-Known Hunter
Nail polish remover may have acetone in it, but it has other stuff, as well. I'm not sure if nail polish remover would be a good idea. Also, ask the person you got it from if it's gelcoated or not. Acetone will not damage a gelcoated surface, but could mess up a raw fiberglass surface. If it's NOT gelcoated, use mineral spirits instead.
 

Jun Garros Fett

Active Hunter
Speaking of mineral spirits and stuff like that.
Don't use goof off adhesive remover on a polycarbonate t-visor. It will melt it. I just found out the hard way on that. :( Guess i have to buy another green face shield next week..

 

judz dwedd

Well-Known Hunter
It might also help to give it a moderate sanding with some fine sandpaper, to dull the surface and get the paint to bond better.
 

Christo Fett

Active Hunter
I've sanded it with all kinds of sandpaper prior to this. I decided to try the "Comet with warm water and a toothbrush" method. I'll report back when I try to prime again.
 

BobaN00b

Active Hunter
christo, i have had the same problem. Not with the primer though. I had the problem once I put paint on top of the chrome. I would get the bubbly, crooked lines. Of course, i was using crap spray paint and when I went out and got the good Krylon, I didn't have the problem anymore.
 

Christo Fett

Active Hunter
Good news!
I just came in from putting on a second coat of primer and it is not lifting or bubbling up at all. The problem had to be silicone residue because the bubbling was around all of the edges and crevases. It seems as though the maker just wiped down the helmet with some kind of cleanser but didn't use a brush to get into the crevases. I washed it down with Comet cleanser like Jun Garros Fett had suggested because this seemed like the safest of all of the chemicals that were recommended and it worked great.
 
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