Not JB Weld, but something similar. I stripped a '57 Chevy, and found a bondo patch about four square feet in size. It was on the rear quarter panel just in front of the wheelwell opening. I pulled the interior panel - this was a business coupe, and had fixed rear quarter windows, so no regulators or such - and found that the panel had been pushed in about an inch plus at the center of the ding. Whoever patched it just drilled about a few hundred holes with a 3/32 or 1/8 inch bit, and buttered the thing up; looked like the inside of a cheese grater in there. I took it to a friend, and he cut it out and put in a new piece of tin.