Paint/Body Corvette Materials, Techniques, and How To

Paint Prep Problem, Any Idea

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Old Sep 14, 2020 | 09:10 PM
  #1  
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Default Paint Prep Problem, Any Idea

This on the top of the right front fender on 68 Ecklers one piece nose. The gelcoat was blocked with 180 then 4 coats of Finish Sand. It was blocked down from 180 to 400 and next step is epoxy primer/sealer. Everything looked good then these holes/chips showed up. I did spray 3M undercoating inside the wheel wells before I installed the nose. Any Ideas what is happening here.
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Old Sep 15, 2020 | 08:44 AM
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Question
Why the epoxy primer over polyester primer ?

They look like fish eyes
can I get a better photo
I would sand them down and see what is under neath
Some thing is the substrate is coming up.
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Old Sep 15, 2020 | 10:45 PM
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Default These are the only ones



The undercoating is not under these areas
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Old Sep 16, 2020 | 05:21 AM
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It looks like air bubbles in te gel coat. its not from your finish.
it is very common in hand laid glass molds. when the gelcoat is poured on brushed on you can get tiny bubbles from stirring or not flowing properly in tighter parts. and they come thru when you cut down the surface.
usually when the manufacture pops the part out of the mold they do a finish sanding to expose bubbles near the surface and they fill em and primer it. but there can always be more if you shape and sand the surface more.

With experience you can start to notice where there are thinning areas with ar pockets beneath, as the surface kinda springs back. you poke with a awl and the bubble is exposed.
some people just clean it good and add filler. some like to use a mini grinder/dremel to bevel edge the area so the filler wont wanna pop out.

air bubbles are really common on fiberglass c3 bumpers, see this thread,
https://www.corvetteforum.com/forums...-corvette.html
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Old Sep 21, 2020 | 11:45 AM
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for sure - something is coming up thru from the under neath
I would sand it down - see what is underneath.
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Old Sep 22, 2020 | 09:58 PM
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Thanks Guys
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