Seeking truth about polyester and water
Thread Starter
Drifting
Joined: Jul 2005
Posts: 1,623
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From: The Netherlands
Seeking truth about polyester and water
Could someone educate me on how the early (or current) corvettes' polyester is protected against for example water osmosis?
I'm reading a lot of crap on forums from people stating all non-pressed molded 'vettes are doomed to form blisters due to moisture getting into the fiberglass.
Didn't GM protect the underside of the fiberglass with resin or some coating to keep water out? I can't believe they wouldn't!
I'm reading a lot of crap on forums from people stating all non-pressed molded 'vettes are doomed to form blisters due to moisture getting into the fiberglass.
Didn't GM protect the underside of the fiberglass with resin or some coating to keep water out? I can't believe they wouldn't!
Race Director
Joined: Dec 1999
Posts: 16,945
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The underside isn't coated because of cost, there will be as much people saying you need to coat it to prevent osmosis as there will be people who will tell you you need to leave it bare to let it breathe. Bottom line being, I don't think osmosis should be a problem as long as you don't submerse your car. Formation of blisters happens on steel cars as well, my truck has blisters after it sat outside 1!!! night under a wet blanket. Now if you keep it under a wet blanket it doens't mean you'll get blisters, it has to do with pre paint prep, my truck was painted too soon after the primer/surfacer was sprayed.
Last edited by Twin_Turbo; Nov 17, 2006 at 04:45 PM.
Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
The Corvette 'glass of any nature will not have water migration thru the back-side to the painted surface. The problem that causes bubbles is that on the top-side of raw 'glass, SMC, FRP, or press molded products is somewhat absorbent. If all the moisture or solvents are not allowed to fully evaporate off of the surface prior to priming, bubbles will occur (sooner or later). One area of concern is oil from the a/c comressor and splashed brake fluid from an un-capped master cylinder have been known to migrate from the underside of the hood to the top surface.
