[chris vickery]

I saw this process a few years ago at the local body shop.
Most bodymen are using this process, it is easier, safer and faster than conventional welding. The advantages are numerous, including no warpage.
Todays automobiles use a very light guage metal for their skins.
The guy I say using it was replacing a panel in a fender. He chose to cut the patch to the appropriate size and then mark out with a magic marker on the to be repaired section. He added an additional 1/2" to be able to form a jotelled edge soas the repair panel would sit upon it and be flush.

It greatly adds to the job it one fits the piece first, trimming as required. He used self tapping sheet metal screws to hold it fimly in place before he applied the adhesive. This acted as the clamping and since he needed to apply a slight skim of bondo afterwards anyhow. Once happy with the fit, he removed the screws, applied the adhesive and replaced the screws to hold it all together until set. After it was a case of removing the screws, quick pass of a sander, apply filler and voila.

He testified that the metal will tear apart before the adhesive will give.