
These are some of the
abrasive choices that were used on the flooring of the other photos. Note, no
grits are more coarse than 50. Also, the discs and screens are not above 120.
These were only used for sanding the bare wood. Finer grits and abrasive pads
were used on the finish.

Note the multiple
species and multiple directions. Angle sanding is very important in these areas
in order to flatten the floor and not “dish” the softer wood.
For the standard finish, which can include coloring from neutral to light and medium staining, the customer can generally expect the following.

Note the shiners in
the upper right; the angle cut had to be re-sanded since the operator missed
complete sanding many of the ends. When stained these are likely to show up.
A smooth surface: the floor should be sanded flat with all mill marks removed and without over wood and under wood. Sander stops, edger digs, and dished grain should be avoided.
The finish itself should be uniform. A consistent gloss level should be present. Puddles, drips, and streaking should not be expected.
The flooring should be sanded only as much as necessary. Over-sanding reduces the life of the flooring and should be avoided.
Of course the corollary is that an occasional mistake of noted exclusions does not cause the floor to fail acceptance. This condition holds as long as the feature is not prominent when viewed from a standing position.

This is a proper
angle cut as it sands all the boards flat.
Now that expectations are set, let’s discuss the actual sanding and finishing processes.

At any time during
sanding, stop, and repair defective pieces. This is the one that will result in
a call back possibly requiring a recoat for the final payment.
Sweep the floor. Embedded grit and debris from other foot traffic must be removed. Vacuuming will likely miss some of this debris.
When sweeping identify and replace or repair problem boards. This includes boards with splits, shake, large broken knots, thin boards and those with bit ends, and other boards with unsound characters. Also, be sure to set all top nails and fasten any loose boards.

Fill after the rough
sanding, then fill and refill missed areas after the medium sanding.
Sanding
The purpose of the first sanding operation or the rough cut is to remove milling marks and flatten the floor. Today’s precision flooring machinery can produce very uniform flooring that requires less sanding than product from 25+ years ago. Normally a 50 or 60 grit sanding paper is sufficient for this purpose. Also, make the first pass on a 15 to 20 degree angle to the direction of the flooring. If the flooring is rough and these grits do not cut the floor efficiently, sand at an increased angle and/or use a coarser grit for the more aggressive cut. The angle cut prevents the sander from rounding and or highlighting board ends and can prevent telegraphing a sanding wave in the floor. With wide plank this is especially important since straight cutting will likely highlight the ends when stain is applied. After the angle cut it is necessary to straight cut the floor using the same grit as the angle cut.
Hand scraping and
hand sanding cannot be avoided. The corners and irregular areas like this stone
hearth must be hand scraped then hand sanded to remove all mill marks in
unsanded areas and create a uniform scratch pattern for staining.

Disc sanding assures
a flat floor without dished grain. Note working along the grain.

Work with the grain
direction to avoid streaking and applicator marks.

Note the puddle by
the bar. Hand sand all the problem areas along with the perimeter before
vibrating or screening between coats. The vibrator or buffer will not be able
to remove excess finish. In this case a scraper was required to remove the
ridge.

Vibrating between
coats; keep the track uniform and with the direction of the flooring. Dust down
window stools, base boards, and other dust holders, then vacuum and tack before
the finial coat. Again, hand work any problem areas.
Again set proper customer expectations, then give the customer a product that meets expectations, and everyone is pleased, you get paid and the customer is your advocate and a source of referral and future jobs.