After doing a 3' x 3' area, with 80 grit paper, I'm thinking I need a bigger unit (this one is 8.8 amp), or courser sand paper, or both. Putting any pressure at all on it bogs the motor down. It's making the underlayment smooth, but taking way too long. Well, off to the store for some more sandpaper.

https://docs.google.com/spreadsheet/ccc?...amp;usp=sharing