You will still need to pre heat the panel up if you go the Lead route. Why not butt weld them together?
Overlap the new panel over the old. Screw it on, cut both to match. I did my first quarter panel that way before the new repro's came out. Worked out pretty good!
You could use a heat wick paste to help lower heat transfer into the quarter panel.
http://www.eastwood.com/coldshield-thermal-paste.html
leading does not require the metal to reach the temperature it would when welding, i've leaded before, no warping whatsoever! that's also on of the reasons i used the flange method, because of the flange, the panel gets extra strength thus eliminating all warping risks.
and i've allready prepped the panels with the flange-seam so no can do on the cutting!
i will punch holes all along the topside of the quarter panel skin for buttwelding so no full weld there.
i was just wondering if there wouldn't be any rust evolving over the years because, eventhough the seam is closed on the outside by lead and on the inside of the car by rubbercompound, there is a minimum hollow space...
i could ofcourse cut the quarter panel a little further so it just touches the bottom edge of the flanged bit on the bodypanel... that would still allow me to do buttwelds on the topside rather than in the punched holes, it would just leave a big gap to fill up with lead...
or just use my fingers to stuff the back-seam full with rubber compound after the leading...
just curious if anyone ever did the flange method before and how it came out, i'm starting to think i went a little hasty on the flanging :-) my friend told me to go at it like that...
oh well, can always blame him if my pricey paintjob goes to sh*t when rust starts coming through!