I have been doing body work on my 70 240 and like most im learning as i go. My roof is is pretty good shape "wavey as most 240z are." However, in one area it looks like a football with a 10 sec hang time came down on my roof and streched the metal. My idea was to heat it up, and bring it back to its original shape( everyone says its so easy). Anyway to make a long story longer its rasied (bubbled) I have heated cooled rapidly, then heated and let cool, slowly while dollying to see if that works better,ect. its not looking good and i dont want to ruin my car. Am i doing something wrong or not doing enough?

The trick is a long cool flame and gradual circular motions around the dent. Heat the whole bump starting from the center and work out. As you do this observe from the side and watch to see it raise slightly. With a large wet sponge dab it from the inside just a little to see it go down. Let it cool the rest of the way by itself. You may have to repeat this a few times but be patient. If it turns blue you got it to hot and now it is to hard. Since your dent is up you should try to pop it in by smacking it with your palm.

Another method is with a shrinking disc but it works about the same and is better with bumps.

My roof looked like it got used for a trampoline!

Edited September 23, 200915 yr by theramz

i am considering the shrinking disc. i am also embarased to say i tried this with a propane tourch, not o2/acc. I didn't think i needed to get my metal that hot to get the results i wanted and now im quiet positive that i didn't heat it up enough.

You don't get it that hot. Blue or even hay colored is too hot. For me the long cooler flame allowed me to gradually heat a larger area like the picture and watch the indent "grow", and quench it just enough to make it come back down. A localized hot spot will warp it unless you are doing very small dings and use a dinging hammer and a dolley.

I had a larger bump on another car and the disc worked a lot better. When it shrank it went flat so I had to bump the crown back in. There is a guy selling 9" and 6" discs on ebay. I prefer the 9" (that's what she said). With the disc you quench on the outside.

I just bought a nine off dagger tools its a nice website if you havn't checked it out. im gonna try the disc first and see if that will work it seems a little less expensive for start up and more forgiving (i hope).