[masraum]

Originally Posted by gregpark

We don't try to drum sand it in one pass. Our first passes with heavy paper are at alternating 45° angles to the room. Followed by passes straight with the grain using finer grits. We sand floors perfectly flat (and faster) that way. You'll be wasting paper and time trying to sand your waves out with an orbital or belt sander.

Right. When I say my floor is not flat, what I mean is that there's no amount of sanding that would get it flat. Downstairs is flat, but upstairs was never meant to be rooms. It was originally attic space. About 35 years ago, someone built rooms. The floors up there are way, WAY out of flat. In one spot, I can put a 4' level down, hold one end on the floor, and the other end is hovering over the floor by more than an inch. In another spot that's probably closer to 5/8". I got the floors fairly flat-ish.

THe first time that we sanded the floor, I rented a drum sander from HD and progressed from 36 --> 120 grit. Then I rented a 7" edge sander and went from 60 or 80 --> 120.

Then because my wife was in a hurry, she stained the floor one day while I was working. The next day, she was super, super unhappy with it (it was pretty bad). So I've now sanded the floors a second time using a drum sander, but this time I skipped the edge sander and used my 4x24 belt sander. Where you see what looks like marks from the drum sander, it's actually from the front edge of the thin pad (1/8") in the center of the belt sander (not from the front roller).

I'm sure that you could/would have done a much better job. I think this is going to turn out OK (certainly rustic, but this place is pretty rustic) once we are done. I'm not going to let the wife do the staining again. I might let her help. I'm sure she could do this, but I don't want to have to sand a third time.