I started sanding my Z to prep for paint and to my horror, the roof was in worse shape than I thought. Paddle sanding reveiled the nightmare ahead. It looked like some kid used it for a trampoline! I had heard about metal shrinking and decided to try it. A semi hot torch and some practice brought about some amazing results. As I heated the indentations one by one starting about an inch outside I saw the metal start to bulge up. I continued in a circular motion to the center and observed a rise of about 1/16high. I quenched it with a wet sponge from the other side and the damage was gone! The process was repeated several times on the larger dents. The last picture shows the results of about 24 hours of work. No body filler required!

 

do you think that might work for a door as well? 2 thanksgiving's ago, some stupid *** kid in a ricer side swiped my Z, and dented in the door. I didn't even know it had happened until after. It dented in the door along where I have the safety trim/door bumper trim, for the extent of the door. It's either buy a new door, bondo the crap out of it, or heat it up as you explained.

 

I tried this on some door dings and they came right out. I haven't tried any deep dents yet but I think it will work. You have to be able to quench it from the back side of the metal. The big bonus was I got the structural integrity of the roof back, no more woop- woop when I push down on it, tight as a drum! I'll show you how I did it when you come to visit.