The floor sanding process was interesting, although I'd seen Ernie (S)anderson (ex USGS) do it to our hall floors in Denver 25 years ago. First they go at the floors with a drum sander (horizontal axis), sanding at about a 30° angle to the flooring. This allows them to cross grain and level out any high spots in the flooring. We're using No. 2 Red Birch, its knotty and has a lot of color variation vs. No. 1 which is more uniform (and monotonous). Some of our floors go 50 ft in one stretch, so monotonous wasn't what we were looking for. After the cross angle sanding with 40 grit, they go parallel to the grain with 80 grit. Now the floors are flat and smooth.
Out comes the filler. There are knots to fill, gaps between boards, and various imperfections—or as we like to call them—Architectural Features. Naive as I am after 18 months at this construction job, I offered to help them put the filler in. Heck I have two putty knives so this could speed things along—NOT. They whipped out a 5 gallon bucket of wood filler (a semi-liquid form) and proceeded to fill everything in one fell swoop with a 14" drywall knife. Sort of like frosting a cake for the Jolly Green Giant. These guys know what they're doing and are fast. They put the putty down in the master bedroom in about 10 minutes, and its about 250 square feet in area. I'd still be getting my little can of putty open to fill some knots. I've learned to just step back, watch, and learn now the professionals make money in these businesses.
After the putty dries (about 30 minutes, but depends on temp and humidity), they go at the floors again, this time with an 80 grit paper on the drum sander. When this sanding is done, they'll go around and find places that have putty wedges (a shallow spot) or spots that need additional putty, and then resurface these spots. After the 80 grit is done, they'll be ready to apply the first of three coats of finish.
While Mike and the drum sander were cutting away, Ivan was doing all the edges with the edge sander. Its basically a disc sander on wheels. He runs it along the walls and all the other edges, like where wood meets tile (see photo to left). The drum sander can get about 1/8" away from the walls, but can't get into the corners. This is where the hand work starts. They use a scraper for the corners, dragging it along grain to take it down to the level of the adjacent floor. After scraping, a rectangular orbital sander is used to get it to the 80 grit level of finish. The thresholds and bull-nose pieces are sanded with a small orbital or by hand, as required.At the end of the day, everything was sanded with 40 grit and about half the floor had been filled and sanded with 80 grit. I suspect the are about 50% through the prep stage (7 hours work for 2 guys), so they should finish all the sanding on Tuesday and apply finish on Wednesday and Thursday. Mike Mills put down three finishes on some test patches.
Two are water base polyurethanes and the third is an old world tung oil finish. We liked the look and feel of the tung oil, and the fact that its easy to reapply to damaged areas, so that what we're going with. In the adjacent photo, its the third (and farthest) finished patch. It tends to enhance grain and darken the wood more than the polyurethanes. When dry it will have a satin (non-glossy) finish and should fell good under foot since this will be a shoe-free house. While all the sanding was going on Nancy did some gardening and I mucked out the garage. A couple hundred pounds of scrap wood was sliced and diced into kindling, the MDF scarps went into garbage bags for the dump, and a whole lot of dust was sucked up into my 35 year old Craftsman Shop Vac. I wish the damn thing would blow up so I could get a new one, but its going to have the best of my and make through this project just to spite me.
