At the opposite extreme of durability are the small rubbers, made of wadding, as mentioned in Art. 6, p. 1090, that are thrown away after a few minutes' use; but this is by many considered to be very wasteful, both of wadding and lacker, and they therefore adopt a medium course, and use one wadding rubber for five or six hours. In this case the wadding is first picked to loosen it thoroughly, and any knotted pieces are rejected; the wadding is then thoroughly saturated with the lacker, and squeezed moderately dry, so as to leave a quantity of lacker proportioned to the size of the work. The wadding is then placed in the middle of a piece of soft linen rag, which is gathered up at the back and tied. Sometimes a piece of sponge is used in the same manner; this forms a durable rubber, but of course it requires to be softened every time before use.
The choice of rubber, however, depends principally upon habit, and is nearly immaterial, provided the rubber is moderately soft, and contains a sufficient quantity of lacker to allow of its being gradually supplied to the work as the polishing progresses; but it is at all times necessary that the rubber should be covered with a piece of soft rag, moistened with a few drops of oil, and renewed as often as it becomes so far clogged up as to prevent the lacker passing freely through it, or that any portion of the lacker on the surface has become so hard as to be likely to scratch the half dry and tender polish.
The work having been thoroughly smoothed with fine glass paper, and the dust wiped away with a clean cloth, the polishing is commenced with free, continuous, and uniform circular strokes, applied with very light pressure, and gradually traversed over the whole surface; and the same process is continually repeated,. varying the position of the strokes as much as possible, but keeping them about the same size, and taking care that every portion of the surface receives an equal but not excessive quantity of lacker, which is regulated partly by the degree of pressure on the rubber, and partly by squeezing it between the fingers.
The principal points requiring attention are, that the pressure is moderate and uniform, that the circular strokes are taken regularly over the whole surface, and that the rubber is never allowed to remain stationary on the work, or be lifted directly from it. Should the pressure be too great, it would be liable to disturb the smooth surface of the tender lacker already applied, and should the pressure or the strokes be irregular, a thicker coat of lacker would be given at some parts than at others. Should the rubber be allowed to remain stationary on the work, it would be liable to adhere to the surface, which would be injured on its removal, and the same injury would be liable to occur if the rubber were lifted directly from the surface, and therefore in removing the rubber it should be slid off at the sides or ends of the work, or if taken from the middle, it should be done with a sweeping stroke, so as to lift the rubber gradually while in motion. Circular strokes are adopted instead of straight strokes, partly because the grain of the wood is filled up quicker and more uniformly, but principally in order to avoid the blemishes which would be almost certain to occur at the end of every stroke taken backwards and forwards, unless the rubber were every time traversed entirely off the end of the work, which is not generally convenient.
The process of polishing is continued until the grain of the wood appears to be thoroughly filled up, and the surface exhibits a uniform appearance, well covered with a thin coat of lacker. It is then allowed to stand for an hour or two to become thoroughly hard, when it is rubbed with very fine glass-paper to smooth down all the irregularities of the grain of the wood, and also of the lacker. The polishing is then repeated, and if it should be found necessary it is again smoothed, and the polishing is persevered in until the surface appears quite smooth, and uniformly covered with a thin and tolerably bright coat of lacker, but which will nevertheless show cloudy marks from the rubber, owing to the presence of the oil, which is finally removed . with a few drops of spirits of wine applied on a clean rubber and covered with a clean soft linen rag, with which the work is rubbed with very light strokes, applied first with a circular motion, and when the surface appears nearly dry, straight strokes are taken lengthways of the grain of the wood, and traversed entirely off the ends of the work; this is continued until the rubber and work are both quite dry, when the polishing will be completed.
The polish, however, will be partly absorbed by the wood in the course of a day or two; and therefore it is desirable to repeat the process after the lapse of a few days, first slightly rubbing down the former coat with very fine or nearly worn-out glass-paper, as it is essential to a smooth and durable surface that the ultimate body of polish should be as thin as possible.
The intricate parts of carved work that cannot be rubbed smooth as explained, are varnished with white hard, or brown hard varnishes, applied with the brush as usual; but the body of varnish should be as thin as possible, particularly in the angles and edges of delicate works, or otherwise the character of the work will be greatly deteriorated. The brown hard varnish is much harder than the white, and from its lesser transparency it does not require quite so much care.
In India, a thin liquid balsam, obtained by incision from the Dipterocarpus terminatus, and one or two other trees, is commonly known under the name wood-oil, and is extensively employed as a varnish for general purposes, and also for the Burmese cups and similar ware. For common purposes the varnish is laid on with a brush, as usual; but for the Burmese ware, the second and subsequent coats of varnish are laid on and smoothed with the naked hand, both in order to preserve a fine surface and to enable the workman to discover and reject any minute particles of dirt. When first laid on, the varnish appears of a light brown colour, but rubbing with the hand changes it to a fine black. When the articles have been varnished, they are carefully shut up in a box to exclude the dust, and then deposited in a deep cold vault for at least three days, which treatment is said to be essential to the proper hardening of the varnish.
The Burmese cups of small size are made of thin strips of bamboo woven together like fine basket-work, and after the first coat of varnish, the interstices of the basket-work are filled up with a paste, made of wood-oil mixed with different fine powders, such as calcined bones or very fine saw-dust from teak wood. After the paste is smoothed with the hand, the article is again returned to the cold vault, and when it is sufficiently hardened, the surface is smoothed with pumice stone and water; the cups are afterwards varnished three or four times, and finally polished after the same general methods as are adopted in this country for varnished works.
Sometimes the cups are ornamented with raised figures, which are made of the same paste that is used to fill up the interstices of the basket-work; the paste is pressed into tin moulds, and afterwards transferred to the bowls; when dry it becomes hard as solid wood. At other times the cups are ornamented with engraved designs, which are afterwards filled up with different coloured powders mixed with wood-oil, after which the surface is smoothed with wet bran held in the hollow of the hand; the operation is generally repeated to insure the complete filling up of all the lines, and the cups are afterwards varnished and polished as usual.
A very good varnish is prepared by the Moochees with shell-lac and wood-oil, heated and mixed in small quantities. They also prepare a varnish for palanquins by melting sandarach and mixing it with boiled linseed oil rendered drying with litharge, but they do not usually add spirits of turpentine in the manner generally adopted in England for making oil varnishes. To give the appearance of gold to the silver leaf used by the Candapilly Moochees for ornamenting boxes, palanquins, and similar objects, a little aloes is dissolved in the varnish, which is laid over it.
J. Rhode, Esq., of Madras, from whose notes the above particulars were gathered, says, "I know of no better or more durable polish, for teak or furniture woods, than may be prepared by melting three or four pieces of sandarach of the size of a walnut or small egg, and pouring upon it a bottleful of linseed oil rendered drying by litharge or other drier, and after boiling them together for an hour, gradually adding while cooling a teaspoon-ful of Venice turpentine. If too thick, it may be thinned with spirits of turpentine. It should be rubbed on the furniture, and after a little time, during which it may be exposed to the sun, rubbed off; the rubbing should be repeated daily, and the polish should not be again applied for eight or ten days, after which it may be slightly applied every one or two months. Water does not injure this polish, and any stain or scratch may be rubbed over with the polish, which cannot be done with French polish."