The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
Coloring Finishing And Painting Wood
Whenever a rubbed finish is desired over several coats of lacquer, two or three days should be allowed for the drying of the last coat before the final rubbing and polishing. The length of time needed for the drying of films or coatings varies somewhat with the different brands of lacquer. The furniture factories which use lacquer often allow only five to twelve hours for drying before rubbing is done.
257. Sanding, Rubbing, and Polishing Lacquer-Films.— Sanding between coats of lacquer is sometimes necessary if for any reason the surface is rough or has other defects that will interfere with the final smooth finish. Sanding can be done with a very fine grade of "Wetordry" sandpaper, used wet, preferably No. 4/0 to No. 6/0. Curved surfaces can be smoothed with very fine steel wool. It is not important to sand between the various coats of lacquer in order to secure proper adhesion, because a new nitrocellulose film will stick tight to an undercoat. If the finisher wishes to apply a coat of varnish over a lacquer-film, it is always wise to sand between coats, because varnish always adheres more satisfactorily to a sanded than to an unsanded surface. The sanding of lacquered surfaces is rather slow work, however, because a coating of this material is exceptionally hard. It is this unusual hardness that prevents the finish from being easily scratched or marred and is, on the whole, one of the good qualities of lacquer.
Rubbing and polishing improve the effect of a lacquered surface just about as much as these same operations soften and beautify a varnished surface. The procedure is very similar in the two cases. Lacquer-films can be smoothed or leveled slightly with wet water-proof sandpaper of a very fine grade, such as No. 6 0 or No. 8/0, before the rubbing process with pumice-stone is begun. Special sandpaper, which should always be used wet, such as automobile sandpaper Nos. 280, 320, and 400, are superior to other abrasives for sanding lacquered surfaces.
Lacquer-coatings or films must be thoroly solidified before any sanding or rubbing is attempted. Altho the surface of a film of lacquer seems to be perfectly dry after a few hours, the coating seldom fully hardens so that it is in proper condition for rubbing under 24 hours, and it is usually wise to allow not less than two or three days for the evaporation of the solvents, in order that the lacquer may not have any soft spots where too thick a coating was applied. Some manufacturers recommend that at least four days be allowed for drying after the application of the last coat, especially on three-coat jobs where only one coat is applied each day.
