80-grit belts are the most common FINAL grit for sanding with the drum sander. If we finish a floor at 100 grit, we usually do it with a buffer or some other, gentler machine that also helps to blend the drum and the edger cuts. The main exception is fir – we like finishing a little finer especially on old fir to help control the splinter risk.
But for every other wood species, we finish on the big machine at 80-grit because it removes the scratch from the 60 grit that came before, it but leaves enough “tooth” or texture in the wood that a finish will soak in and bond well to it. This is a hard pill to swallow for many woodworkers or auto-body finishers – they really want to hear that we finish around 200 or 300-grit to get that sweet, smooth finish. But remember, floors are designed to be walked on, and we need to make sure we leave enough texture in the wood so that the finish will hold, when we tromp across with our rough, dirty shoes. Don’t worry – it will be smooth enough that your babies can crawl across with harming their hands, but still bonded well enough that they can run across it when they get older.
Allow 1 belt for every 250-300sqft