I use an 8 inch featheredge pad on a variable speed air sander, and 36 or 40 grit discs. It is flat, and will kind of block sand at the same time. I then go back over it with 80 grit and a pad, and circle sand by hand to get rid of the leftovers. I can strip a car in a day, and it is ready for metal prep, and a heavy priming with 2K primer.