Paste filler is sold by the pound in cans of various sizes. The best fillers are made of ground rock crystal mixed with raw linseed oil, japan and turpentine.
For preserving the natural color of the wood, filler is left white; for Flemish, it is colored brown; for antique and weathered finishes, it is dark. Fillers can be purchased ready colored.
151. Filling with Paste Filler.
—(1) Thin the filler with turpentine until it makes a thin paste. (2) With a stiff-bristled brush, force the filler into the pores of the wood and leave the surface covered with a thin coating. (3) Allow this to stand until the filler has “flatted,” that is, until the “gloss” has disappeared and the filler becomes dull and chalkish. The time required for this to take place varies. Twenty minutes is not unusual. (4) Rub the filler off just as soon as it has flatted—do not let it stand longer, for the longer it stands the harder it is to remove. Rub across the grain as much as is possible, using a wad of excelsior. Finish fine work by going over it a second time with a cloth, rubbing with the grain as well as across, that the “high lights” may be clear of filler.
On fine work use a felt pad to rub the filler into the pores, and rub off with a cloth only.
Twenty-four hours should be allowed the filler to harden. One filling is sufficient for ordinary work; on fine work the above process is sometimes repeated after the first filling has hardened.
The striking contrasts in the grain of wood such as oak and chestnut, obtained by the use of colored fillers, are due to the dark filler’s remaining in the open grain but being wiped off of the close grain—the “high lights.”
On quarter-sawed oak, each flake is sometimes sanded with fine paper, No. 00, to remove the stain that the contrast may be sharper.
Excelsior and rags used in cleaning off filler must not be allowed to lie around but must be burned for they are subject to spontaneous combustion and are dangerous.