The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
Coloring Finishing And Painting Wood
End-grain sanding is just as important as sanding of the surfaces and edges. If the end-grain is left too rough, additional stain will be absorbed there; consequently it will become darker than other portions of the surface.
Curved surfaces can be sanded to best advantage with split sandpaper, as described on p. 27. Double-coated paper for splitting is now sold on the market. The split sandpaper is most effective for some kinds of work when dampened or moistened on the back. Water, benzine, and turpentine, or turpentine substitutes, are used for moistening sandpaper either to keep down dust or to make the paper more pliable.
The use of sandpaper between the successive coats of finish is necessary in securing a level surface and proper adhesion of the films of shellac, varnish, or lacquer that are to be applied later on in the finishing process. The kind and size of sandpaper, and the method of using it, depend upon various conditions. Three types of sandpaper are used by wood-finishers:
(1) standard paper, with either flint or garnet grit; (2) split or double-coated paper; and (3) waterproof sandpaper. The standard and split types have already been described in previous paragraphs of this section. Water-proof sandpapers have been developed to help solve several problems of the finishing-room.
The use of such papers enables a workman to sand a moist surface of wood soon after it has been sponged thereby saving a certain amount of time. Sanding with wet paper reduces the dust in the room which helps to preserve the health of the finisher and to reduce danger of specks in varnish finishes. For sanding moist wood to remove fuzz, rather fine grades of grit, such as sizes 1/2, 0, or 00, should be used in most cases.
Waterproof papers, which do not lose their grit when thoroughly dampened and kept in that condition during several minutes, are often preferred for rubbing between coatings of varnish; and, when used over a rubber or felt block, they produce a level surface without gloss, more quickly and more satisfactorily, between the first coats especially, than does pumice-stone. The sanding should all be done lengthwise of the grain only, where this is possible, and fine grades of grit, such as the 5/0 to 8/0, leave an excellent surface for refinishing.
Automobile painters are using a special sandpaper which can also be used wet. Automobile finishers' sandpaper is sold by number; such as No. 280, rather coarse; No. 320, medium in grit; and No. 400, very fine. These sandpapers are used for smoothing undercoats and surfaces of lacquer which must be made level in preparation for the next coat.
They scratch if they are used dry, and for this reason they are kept wet when rubbing varnished or lacquered surfaces.
