Quarter sailpanel seams. Lead filler or ???

[The WidowMaker]

It's not the movement, it's the hardened mig weld vs the normal sheet metal. It'll expands differently with heat. And it's worse at a place like the top of the b pillar, where sun would hit in directly.

ive heard a lot of possible explanations and thats one of them. others have been filler shinkage (although some say there car sat for a year before painted) and ive also heard joint prep/design with some using a butt weld and others using a lap weld. it would be interesting to take the temp of the body panels and see if there was any real difference between parts that are doing it. i have a few areas that have been worked and mig'd back up, and im planning on doing the marker lights soon. id rather not deal with any hairline cracks.

also, why would a chunck of lead in a seam not expand any different than the surrounding sheet metal?

sorry for the hijack.....