You dont need acetylene.. hell I did some with a little butane torch.. mapp gas works well and you are less likely to do something very very bad.
I dont mean to conflict with the advice.. maybe I am wrong but it worked fine for me.. the trick is cool it with a wet rag.. Work it with a body hammer kit.. harbor freight sells cheap ones that work fine.. get it as close as possible and roughen it up with 60 grit and use body filler.. Maybe if its really hot out youd need acetelyne..
Again, good advice Im just sayin it worked for me and I do have acetelyne.. just less risk.