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ok guys, ive got guy here that wants me to fix crappy body kit, its got thousands of tiny pin holes in fiberglass and then he sprayed some "dimensions" brand primer(a.k.a. crap) lol and then it dried. You guessed right it pin holed all up again. what would you suggest to fix that, I thought maybe taking time and laying skin coats of polyester putty and then sanding it down till smooth.
 

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That is what I would suggest. If they are pin holes as you say then one coat of poly should fill them and then just block sand it.
 

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I hate to sound like an alarmist, but pinholes over a fresh FRP surface sounds to me like a possible "root cause" might be mold release residue left on the gel coat berfore attempting to paint. Especially a silicone-containing mold release. Before doing any more work on this, I'd try a cross-hatch adhesion test to make sure that you have some adhesion between the gel coat and the first coat of paint that's already on there.

BarryK or MartinSr, do you concur with my opinion on this?

If this proves to be the case, I'd sand thoroughly, then give a good solvent wipe, before putting any additional coatings of any sort on.
 

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this is probably the case if it is a fisheye and only in the primer but fiberglass is known for pinholes usually where the gelcoat is sanded through or i have even seen some real crap body kits with no gelcoat at all which are a nightmare but if there is a pinhole in the glass it will usually just get bigger and bigger the more coats of primer you put on unless you really drench it enough to fill the hole which is a no no! if its fisheyes from mold release then sand all the primer off, clean with wax and grease remover a couple times and reprime. if its pin holes in the glass then a nice TWO PART glazing putty will work fine. evercoat metal glaze or equivalent. by the way...welcome to the world of fiberglass body kits. 90% of them out there are crap and never fit right. i love the customers who buy the body kit off ebay for $400 that someone copied in their back yard. of course its a copy of a copy of a copy of an original that isn't right to begin with. they all wonder why there is $1200 in fiberglass and bodywork to get it right.
 

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powderbill said:
I hate to sound like an alarmist, but pinholes over a fresh FRP surface sounds to me like a possible "root cause" might be mold release residue left on the gel coat berfore attempting to paint. Especially a silicone-containing mold release. Before doing any more work on this, I'd try a cross-hatch adhesion test to make sure that you have some adhesion between the gel coat and the first coat of paint that's already on there.

BarryK or MartinSr, do you concur with my opinion on this?

If this proves to be the case, I'd sand thoroughly, then give a good solvent wipe, before putting any additional coatings of any sort on.
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Exactly right, and some of these are just plain not cured out! You see a lot of these problems with shops that do customizing. Some of these parts come in very uncured.
Some we have sanded epoxy or primer back off and left in the sun for a few days some for weeks.
Some times a short wave or medium wave light will help to cure out panel but I will say we have had mixed result with these lamps in this situation.

We have also found that if you get the panel somewhat cured out and you spray a coat of epoxy over the glass again, if the epoxy does not "Fish-eye" but only minor has minor pinholes
than we have found that the epoxy will have a good bond.
To test this you need to let the panel set 24-48 hours than use duct tape in a number of spots.

We have had a number of parts that never would cure out- many and many!
.
 
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