Knotted or cross-grained wood cannot be planed with the planes used for deal, but with a special tool, of which the iron is placed at a more obtuse angle. These planes can be had in wood or metal, and are in general use by cabinet-makers. They are named according to the angle at which the iron is placed. For deal and soft wood this is 45 degrees, or York pitch; while the iron set at 55 degrees, middle pitch, or 60 degrees, half pitch, is used for molding planes for soft and hard wood. When the latter is, however, very knotty, it is worked over in all directions with a toothing plane, so as to cut across the fibres and reduce the surface to a general level. It is then finished by the scraper, often a piece of freshly broken glass, but more properly a thin plate of steel set in a piece of wood, and ground off quite square. The edge is then often rubbed with a burnisher, to turn up a slight wire edge. This will scrape down the surface of the wood until it is ready for " papering," i. e., being further smoothed by glass or sandpaper. This is to be rubbed in all directions, until the work has an even surface, and the lines thus produced are further reduced by the finest sandpaper, marked 00. After this it is rubbed over with a bit of flannel, dipped in linseed oil, and allowed to dry. This oiling is then repeated, and the work again set aside for a day or more, until the oil is fairly absorbed.
If the wood be porous it must first be filled, as it is called, and for this nothing is better than whiting colored so as to resemble the wood and kept dry. Rub the wood with Linseed oil and then sprinkle it with whiting. Rub the latter well in, wipe it off carefully and give time to dry. This is far superior to size.
The polish - French polish - is made by dissolving shellac in alcohol, methylated spirits, or even naphtha. This is facilitated by placing the jar or bottle in a warm place, on a stove or by the fire. Other gums are often added, but are not generally necessary. In short, no two polishers use precisely similar ingredients, but shellac is the base of all of them. The following recipes have been collected from various sources more or less reliable:
1. Shellac, 4 oz.; alcohol, 1 pin ....2. Shellac, 4 oz.; sandarac, 1/2 oz.; alcohol, 1 pint.....3. Finishing polish: Alcohol (95 per cent.), 1/2 pint; shellac, 2 dr.; gum benzoin, 2 dr.; put into a bottle, loosely corking it, and stand it near a fire. shaking it occasionally. When cold, add two teaspoonfuls of poppy oil, and shake well together.
These, it must be remembered, are polishes to be applied by means of rubbers, and not by a brush. Those used in the latter way are varnishes, such as are applied to cheap wares and also to parts of furniture and such articles as are carved and cannot in consequence be finished by rubbing.
The polisher generally consists of a wad of list rolled spirally, tied with twine and covered with a few thicknesses of linen rag. Apply a little varnish to the middle of the rubber and then enclose the latter in a soft linen rag folded twice. Moisten the face of the linen with a little raw-linseed oil applied to the middle of it by means of the ringer. Pass the rubber quickly and lightly over the surface of the work in small- circular strokes until the varnish becomes nearly dry; charge the rubber with varnish again and repeat the rubbing till three coats are laid on, when a little oil may be applied to the rubber and two more coats given it. Proceed in this way until the varnish has acquired some thickness; then wet the inside of the linen cloth, before applying the varnish, with alcohol, and rub quickly, lightly and uniformly, the whole surface. Lastly, wet the linen cloth with a little oil and alcohol, without varnish, and rub as before till dry. Each coat is to be rubbed until the rag appears dry, and too much varnish must not be put on the rag at one time. Be also very particular to have the rags clean, as the polish depends in a great degree upon keeping everything free from dust and dirt.
To insure success the work must be done in a warm room, free from dust.
Turned articles must be brought to a fine smooth surface with the finest sandpaper, and the direction of the motion should be occasionally reversed so that the fibres which are laid down by rubbing one way may be raised Tip and cut off. To apply the polish, which is merely a solution of shellac in •alcohol, take three or four thicknesses of linen rag and place a few drops of polish in the centre; lay over this a single thickness of linen rag and and a drop or two of raw linseed oil over the polish. The rubber is then applied with light friction over the entire surface of the work while revolving in the lathe, never allowing the hand or mandrel to remain still for an instant, so as to spread the varnish as evenly as possible, especially at the commencement, and paying particular attention to the internal angles, so as to prevent either deficiency or excess of varnish at those parts The oil, in some degree, retards the evaporation of the spirit from the varnish and allows time for the process; it also presents a smooth surface and lessens the friction against the tender gum. When the varnish appears dry, a second, third and even further quantities are applied in the same manner, working, of course, more particularly upon those parts at all slighted in the earlier steps.