I can't offer any better advice than what has already been given, but I CAN offer a warning: don't buy your sandpaper from Harbor Freight! That is by far the worst sandpaper I have ever used, and I have used a lot. That crap will tear almost immediately., whether you are using a block, sponge, your hand, whatever, it's going to tear. I can't remember the brand off the top of my head, but it didn't seem to matter; I bought a couple of packs of different grit and different brand thinking it was a bargain, it is not.