In the process of straightening my inner fenders - someone apparently stepped on one of them at some point and there was a 1/2" deep dent in the shape of a shoe sole.

I hammered and dolly-d out the dent to some extent and then filled the rest in, but am having trouble achieving the round contours of the surface. Can't really use a long board in that there is no continuously straight edge to use as a guide.

I could probably continue to work the metal and get it a bit straighter, but the neighbors aren't real keen on the continued banging. As a result, I jumped the gun a bit and used more filler than I needed to, but on the inner, I'm not too worried.

Anyway, how to sand a compound curve that resembles a ball? Tough chore!

Ok, this is going to sound a little strange but give it a try. I have been doing this stuff for about 30 years and have spent a LOT of time on older 30s type cars. I look at ever panel the same, as if they are "flat". What you have there is merely a "curved flat". :) No kidding, sand it with a short block and just feel a short area of filler along the edge of the filler. Run your hand from the straight metal onto the filler, but not all the way across. At least not to try to correct it all, you can run your hand across but only focus on the first half inch or so. When that half inch is the same contour as the metal, move on to the next half inch, then the next then the next.

That is how I have been doing rounded surfaces for years.

Brian

Yeah, that's pretty much the best I could come up with. If it were a simple curve, I could follow the flat area and it's be no problem, but the 360* compound curve leaves nothing other than best guess I suppose...