Bondo Glazing and Spot Putty lifted primer

This message is a reply to an archived post by ih560 "Bondo Glazing and Spot Putty lifted primer".



I confirm a problematic experience with "Bondo Red Glaze Putty" pinhole and small cracks filler. I filled a couple of pinholes in my primer with this filler, let it cure for a couple of days, sanded over it to obtain a perfectly fine surface, primed over again and waited another 24 hours. That's a total of 72 hours cure time for the Bondo filler that requires only 3 hours. Result:

cracks in the paint everywhere the Bondo was applied over a surface 4 to 5 times the size of the applied area. It is a chemical reaction that has nothing to do with acids or cure time or what have you.

Stubborn as I am, I tried it again over a plastic bumper this time leaving plenty of cure time and double the amount of primer over the putty to isolate it from the base coat. I let it all dry as much as can be dried. Then, I passed the base coat of urethane Chrysler PB2 (metallic + pearl light blue).

Result: Cracks within 24 hours.

I join a link to my poof of purchase. You can find my product review there.

I had used this Bondo product with paint that was not urethane based for good results. Nevertheless, I find it annoying that such a poor quality product be sold by a big brand without the proper warnings written in big on the package. I call it commercial suicide.

I am now looking for a good putty that would do the job for a good result. [b:654c4848f0]Any suggestion?[/b:654c4848f0]
Paint PB2 that reacted to the Bondo

I have used PPG and two other popular brands that sell at car Quest and other auto stores but not "bondo brand". I have never had a shrinkage/crazing/bleed through problem with any. These are 2K catylized paste in can type glaze puttys and not the squeeze tube liquid type or the "old" non catylized laquer spot putty in tube (trash). I usually get on it and finish it with no more than 1hr cure time. Never heard of the problem you mention.

Simply put, laquer spot putties do not belong in todays modern world of paint.
They are fine with laquer, enamel or acryllic enamels.

If Bondo red glaze putty is the same product as Nitro Stan or red lead it is so obsolete I don't know why they even sell it anymore. For a two part spot putty try Dolphin Glaze. For a good filler try Evercoat The modern spot puttys that mix don't have the shrinkage of the old red lead. I am assuming you primed over the filler first.I don't know what caused your failure.

That's why I don't use that stuff. I use what I know works which is a good grade of bondo and a good sandable primer. I have epoxy primer but have never used any ever.