All of these guys are giving fantastic info. You'll just have to figure out the way to do it with the equipment you have. I screw the pad onto the gun and use a pencil to go around the pad. The lead is hard to rub off when I am grinding/sanding. Some people use a scribe and fill the line in with chalk. Either way, like they said, when you get close, do the rest by hand. (I started doing pads by locking my Sears beltsander in my vise upside down at 45* angle and locking the trigger on using the lock button. Then I would plug it in. Now I use a vertical beltsander.) The more time you take, the better the job. I use transmission fluid, like Yeti. I pour some in the cap and rub it on the pad with my finger in the place I want to sand. It keeps the pad from coming apart in chunks and you can use pretty coarse sandpaper and it still looks smooth. That way I don't have to freeze them. Take your time and when you do the heel/toe, make sure you go slow and get the angle right. Keep checking by screwing the pad on the gun to check your progress. Let us know how it comes out. Good luck.
