Weld seams showing through new paint job

[MrQuick]

I would think it was due to filler shrinkage. Not enough prep time?

[Jim Nilsen]

On my 1st 67 camaro I put a laquer paint job on it myself and the leaded seam at the roof line would always start to show with an orange peel look after about 6 months and then I would buff it and it would go away. It was always a mystery to me.
I painted my 67 that I have now and it has never done the same thing. I used acryilic enamel on the new paint job with an epoxy primer. The best I can think of is that it is the primer that causes it to happen. I used a sandable primer only on the first car instead of an etching type primer sealer as a base. I didn't have a lot of money to buy the paint much less the right primers at the time. So my guess is that it is either the fault of the primer job not being done very well or with inferior materials . I really don't think you have laquer paint but I don't know that for sure.

So it could be the bondo?

Maybe some will have an explanation for what makes it happen but I understand your frustration.

[Rick Giles]

I was curious if it had anything to do with the actual weld. And maybe not the bondo/primer application or the product used. I've seen this on some cars. And the reason I'm asking is I have a 69 Camaro with the original quarters with rust issues in the usual areas over the rear tires. But it has an awesome fit around the trunk lid. I really hate to mess that up. Not to mention all the factory joints and welds. Just don't want to have the same problems with the quarter patches later with weld lines coming back.