If using the flap disk BEWARE. After seeing a comment about using the flap disk I decided to give it a try...or rather have my son give it a try. I had two boxes of flap disk, along with some free labor and figured why not. Well, the 4 1/2" Milwaukee runs at better than 20,000rpms. I glanced over to see how things were going and the side of the panel looked like a woodpecker had been pecking on it in spots. Well, its seems that my son was going at it with the flap disk to straight and it would actually indent the metal some. The way the light was shining on it he couldn't tell but boy I sure could from where I was standing! It'll have to have a light skim coat of filler to smooth it back up. Just thought I would let you know MY experience and to BEWARE
