THE various processes to which wood is treated under this head accomplish one or more of these results: (i) They preserve it; (2) they make it easy to keep clean; (3) they beautify it, by bringing out the grain or by covering it with a uniform colour.
Paint has long been the standard finish for woods of cheap quality exposed to the air, for inside and outside work. It is a preservative, filling the pores of the wood with pigments mixed with oil; and it satisfies the tastes of all, being made in an infinite variety of colours, shades and tints. It conceals knots, cracks and other defects, producing a smooth, shining, uniform surface.
"Graining" is a base imitation of the natural grain of oak and other woods. As a child I watched a man at this work. Yellow paint had dried fairly on a cheap, white-pine door. A light brushing of brown paint was spread unevenly over one panel. Then one thumb, wrapped with a rag, was dipped into the brown paint, and a knot with radiating brown streaks was set in each end of the panel. One or two scattered little knots were thrown in for good measure. Then the artistic thumb retired, and a comb came into commission. The blade of it drawn over the plain brown field scraped off narrow lines of the dark colour and left the yellow showing through in parallel, alternating lines. An agitated sidewise motion of the comb produced a "curly" patch on a field intended to imitate the grain of oak with its spring and summer wood of alternating yellow and brown.
There may be such a thing as good graining. I can see only ugly, insincere imitation in it. A painted door makes no pretence to be a hard wood, therefore it is honest. A grained door is not.
Staining. Pigments dissolved in water or in other liquids stain wood to any desired colour. Nut galls and various dyestuffs are used for this purpose. Creosote oil, properly coloured, is a popular stain for shingles. It is a preservative, and gives a soft, dull finish, being absorbed without concealing the texture of the wood. This sort of staining is a far more artistic colour process than painting, when the outside finish of houses is con sidered. Being a rough finish, it is not employed on interiors
unless a rustic scheme is being followed.
Staining is also an important part of the finishing of ex pensive hardwood interiors. Even the best white oak is treated to a little yellow to give it a creamier colour. "Weathered oak" owes its age to fumes of ammonia or to burnt umber as a rule, and Flemish oak to darker dyes. The bog oak of Ireland is black as soot, but an imitation is produced by staining any of our oaks black. It takes a connoisseur to tell the genuine from the bogus. Ebony and teak are easily imitated. Elm masquerades as oak, birch as mahogany. Yet staining is a legitimate practice. The handsomest of mahogany has had a little Venetian red worked into its pores to brighten the grain and make the colour even.
Filling. Coarse-grained woods are very porous and easily dented, and do not take a good polish unless a filler is used. A great many different substances are used to replace the air in these wood cells. In fact there are very few woods that are not both filled and stained before they are ready to be polished. "White fillers" are tinted before they are applied. Some woods are filled with plaster of Paris, moistened with water or spirits after being rubbed into the surface as a powder. Whiting and pumice are also used. Glue and patent wood sizings, even tallow with plaster of Paris, are used. A popular filler is ordinary varnish. When the filler is dry the surface is hard and ready for the finishing process.
Varnishing. Varnish is made by dissolving shellac in spirits. The volatile liquid elements dry away, and a shiny, hard coating of the shellac remains. It shows white lines when scratched with a pin: Varnish combined with stain is a popular finish for cheap woodwork. The best varnish is made of white shellac; through it the grain of the wood shows as if through a pane of polished glass.
After the filler, which raises the grain into a rough surface, there is a rubbing down with pumice or fine sandpaper. Other wise the varnish emphasises the roughness.