Sanding the Piano Plate with Water and Soap

​It has been always a struggle trying to decide if the plate should be sanded wet or dry. Mr. David Betts taught us to wet sand with water. Many rebuilders prefer sanding dry. After a number of experiments for the last 9 years, I find sanding with water and a little bit of soup works the best for now.

After the plate is well vacuumed, apply putty into the divots and dents, leaving the filler a little protruding over the plate surface. The putty is a mixture of base and hardener. Once mixed, it dries fast. Several rounds of filling maybe needed. Let dry for an hour.

If sanding dry, the worker may inhale a huge amount of dust even with mask on. I usually feel the throat and stomach uncomfortable after sanding. The dust is so fine, almost invisible, but it is all over the atmosphere. A vacuum can only do so much to suck away the dust. Imagine the old metal powder smell combined with the roaring vacuum noise. A day can feel like a few years.

To wet sand, fill a bucket with about half gallon of water and a few drop of Murphy wood cleaner. Pour some of the soap mixture into a deep dish. Dip 320 or 400 grit sandpaper into the liquid, sand the plate in circular motion. After a few sanding strokes, swish the paper in liquid to wash off the wet dust. Feel the plate with fingers to see if the surface is smooth. Light sanding works better than aggressive heavy pressure.

Water can cause the plate to rust for sure. Wipe off the wet dust from the plate constantly with rags, so the surface can be kept dry. When the liquid in the dish is dirty and muddy, dump the liquid and wash the dish. Fill with clean soap water and continue sanding.

After the first round of sanding, more divots maybe discovered and they will need to be filled with putty, then sanded again. Keep working until satisfied. It takes about 8 to 16 hours depending on how fussy the worker is.

​At the end, wipe the whole plate dry and clean. Now the plate is ready for new finish.