Why cant you use sanding sealer instead of going to all of the trouble of grain filling with pumice?
Sanding sealers were developed primarily for industrial use as a sealing base for chemical based lacquers. They are usually required to be sprayed on and sanded to provide a smooth finishing surface. They do not actually fill the grain unless you spray on at least 5 coats, sanded between each coat. This buildup of thick finish material is exactly what the French polishing process avoids. We have also found that sanding sealers have very poor adhesion properties. After a period of time, areas of the finish will tend to lift and flake.
