LACQUERS
(See also Enamels, Glazes, Paints, Varnishes, and Waterproofing.)
Lac And The Art Of Lacquering.
The art of lacquering includes various steps, which are divulged as little as possible. Without them nothing but a varnish of good quality would be realized. Thus in Tonkin, where the abundant {438} production is the object of an important trade with the Chinese, it is so used only for varnishing, while in China the same product from the same sources contributes to most artistic applications.
When the Annamites propose to lacquer an object, a box, for example, they first stop up the holes and crevices, covering all the imperfections with a coating of diluted lac, by means of a flat, close, short brush. Then they cover the whole with a thick coating of lac and white clay. This clay, oily to the touch, is found at the bottom of certain lakes in Tonkin; it is dried, pulverized, and sifted with a piece of fine silk before being embodied with the lac. This operation is designed to conceal the inequalities of the wood and produce a uniform surface which, when completely dry, is rendered smooth with pumice stone.
If the object has portions cut or sunk the clayey mixture is not applied, for it would make the details clammy, but in its place a single, uniform layer of pure lac.
In any case, after the pumicing, a third coating, now pure lac, is passed over the piece, which at this time has a mouse-gray color. This layer, known under the name of sou lot, colors the piece a brilliant black. As the lac possesses the remarkable property of not drying in dry air, the object is left in a damp place. When perfectly dried the piece is varnished, and the desired color imparted by a single operation. If the metallic applications are excepted, the lac is colored only black, brown, or red.
The following formulas are in use:
Black.—One part of turpentine is warmed for 20 minutes beyond the fusing point; then poured into 3 parts of lac; at the same time pheu deu (copperas) is added. The mixture is stirred for at least a day, sometimes more, by means of a large paddle.
Maroon.—This is prepared by a process similar to the preceding, replacing half of the copperas by an equal quantity of China vermilion.
Red.—The lac, previously stirred for 6 hours, is mixed with hot oil of trau, and the whole is stirred for a day, after which vermilion is added. The latter should be of good quality, so as to have it brilliant and unchangeable.
The operation of lacquering is then ended, but there are parts to be gilded. These are again covered with a mixture of lac and oil of trau. When this layer is dry the metallic leaves are applied, which are themselves protected by a coating, composed also of lac and oil of trau. All these lac and oil of trau mixtures are carefully filtered, which the natives effect by pressing the liquid on a double filtering surface formed of wadding and of a tissue on which it rests. It can only be applied after several months when the metallic leaf is of gold. In the case of silver or tin the protecting coat can be laid on in a few days. It favorably modifies the white tints of these two metals by communicating a golden color. The hue, at first reddish, gradually improves and acquires its full brilliancy in a few months.
Little information is procurable concerning the processes employed by the Chinese. The wood to be lacquered should be absolutely dry. It receives successive applications, of which the number is not less than 33 for perfect work. When the lac coating attains the thickness of 1/4 of an inch it is ready for the engravers. The Chinese, like the inhabitants of Tonkin, make use of oil of trau to mix with the lac, or oil of aleurites, and the greatest care is exercised in the drying of the different layers. The operation is conducted in dim-lighted rooms specially fitted up for the purpose; the moisture is maintained to a suitable extent by systematically watering the earth which covers the walls of this “cold stove.”
Lacquer For Aluminum.
Lacquer For Brass.—
| Annatto | 1/4 ounce |
| Saffron | 1/4 ounce |
| Turmeric | 1 ounce |
| Seed lac in coarse powder | 3 ounces |
| Alcohol | 1 pint |
Digest the annatto, saffron, and turmeric in the alcohol for several days, then strain into a bottle containing the seed lac; cork and shake until dissolved.
Lacquer For Bronze.
II.—The following is equally suitable for boots and leather goods as for application on iron, stone, glass, paper, cloth, and other surfaces. The inexperienced should note before making this liquid that it does not give a yellowish bronze like gold paint, but a darkish iridescent one, and as it is a pleasing variation in aids to home decoration, it would doubtless sell well. Some pretty effects are obtained by using a little phloxine instead of part of the violet aniline, or phloxine alone will produce a rich reddish bronze, and a lustrous peacock green is obtained with brilliant aniline green crystals.
Quantities: Flexile methylated collodion, 1 gallon; pure violet aniline, 1 pound. Mix, stand away for a few days to allow the aniline to dissolve and stir frequently, taking care to bung down securely, as the collodion is a volatile liquid, then strain and bottle off. It is applied with a brush, dries rapidly, and does not rub off or peal.
Celluloid Lacquer.
Colored Lacquer.
Apply with a soft camel’s-hair brush; it is better to use too small a brush than too large. When complete, warm the articles for a few seconds before a clear fire; the hotter the better; if too hot, however, the colors will fade. This makes the lacquer adhere firmly, especially to metallic surfaces. Aniline green works very well.
Lacquer For Copper.
Ebony Lacquer.
Gold Lacquers:
I.—For Brassware.—A gold lacquer to improve the natural color of brassware is prepared from 16 parts gum lac, 4 parts dragon’s blood, and 1 part curcuma powder dissolved in 320 parts spirits of wine in the warmth and filtered well. The articles must be thoroughly cleaned by burning, grinding, or turning either dull or burnished, and then coated with a thin layer of the above mixture, applied with a soft hair brush or a pad of wadding. If the objects are colored the lacquer must be laid on by stippling. Should the color be too dark, it may be lightened by reduction with a little spirit until the correct shade is produced. The most suitable temperature for the metal during the work is about the warmth of the hand; if too hot or too cold, the lacquer may smear, and will then have to be taken off again with spirit or hot potash lye, the goods being dried in sawdust or recleaned as at first, before applying the lacquer again. Round articles may be fixed in the lathe and the lacquer laid on with a pad of wadding. In order to color brassware, a solution of 30 parts caustic soda; 10 parts cupric carbonate; 200 parts water (or 200 parts ammonia neutralized by acetic acid); 100 parts verdigris, and 60 parts sal ammoniac is employed, into which the warmed articles are dipped. After having dried they are coated with colorless shellac varnish.
II.—For Tin.—Transparent gold lacquer for tin (all colors) may be made as follows: Take 1/2 pint of alcohol, add 1 ounce gum shellac; 1/2 ounce turmeric; 1 1/4 ounce red sanders. Set the vessel in a warm place and shake frequently for half a day. Then strain off the liquor, rinse the bottle and return it, corking tightly for use. When this is used, it must be applied to the work freely and flowed on full, or if the work admits it, it may be dipped. One or more coats may be given as the color is required light or dark. For rose color substitute 1/4 ounce of finely ground lake in place of the turmeric. For blue, substitute Prussian blue. For purple, add a little of the blue to the turmeric.
For Bottle Caps, etc.—
| I.— | Gum gutta | 10 parts |
|---|---|---|
| Shellac | 100 parts | |
| Turpentine | 10 parts | |
| Alcohol | 450 parts | |
| II.— | Gum gutta | 40 parts |
| Dragon’s blood | 5 parts | |
| Alcoholic extract of sandalwood | 5 parts | |
| Sandarac | 75 parts | |
| Venice turpentine | 25 parts | |
| Alcohol, 95 per cent | 900 parts |
Mix and dissolve by the aid of a gentle heat.
Liquid Bottle Lac.
Lithographic Lacquer.
Lacquer For Microscopes, Mathematical Instruments, Etc.
To Fix Alcoholic Lacquers On Metallic Surfaces.
Lacquer For Oil Paintings.
Lacquers For Papers.
II.—With base of lime: Dissolve 30 parts red lithol R or G in paste of 17 per cent, in 300 parts of hot water. Boil for a few minutes with an emulsion prepared by mixing 10 parts sulphate of alumina with 100 parts of water and 2.5 parts of slaked lime in 100 parts of water. Filter after cooling.
Lacquer For Stoves And Other Articles To Withstand Heat.
Miscellaneous Recipes:
Russian Polishing Lac.—
| I.— | Sticklac | 925 parts |
|---|---|---|
| Sandarac | 875 parts | |
| Larch turpentine | 270 parts | |
| Alcohol, 96 per cent | 3,500 parts |
The sticklac is broken up and mixed with the sandarac, put into a suitable container with a wide mouth, the spirit poured over it and set aside. After standing for a week in a warm place, frequently stirring in the meantime (best with a glass rod) and fully dissolving, stir in the turpentine. Let stand 2 or 3 days longer, then filter through glass wool. The sandarac dissolves completely in the spirit, but the stick leaves a slight residue which may be added to the next lot of lac made up and thus be treated to a fresh portion of spirit. The larch turpentine should be of the best quality. This lac is used by woodcarvers and turners and is very much prized by them.
Mastic Lac.—
| II.— | Mastic, select | 150 parts |
|---|---|---|
| Sandarac | 400 parts | |
| Camphor | 15 parts | |
| Alcohol, 96 per cent | 1,000 parts |
Prepare as directed in the first recipe.
Leather Polish Lac.—
| III.— | Shellac | 16 parts |
|---|---|---|
| Venice turpentine | 8 parts | |
| Sandarac | 4 parts | |
| Lampblack, Swedish | 2 parts | |
| Turpentine oil | 4 parts | |
| Alcohol, 96 per cent | 960 parts |
The alcohol and turpentine oil are mixed and warmed under constant stirring in the sand or water bath. The shellac and sandarac are now stirred in, the stirring being maintained until both are dissolved. Finally add the turpentine and dissolve. Stir the lampblack with a little vinegar and then add and stir in. Instead of lampblack 125 to 150 parts of nigrosin may be used. This lac should be well shaken before application.
LACQUERED WARE, TO CLEAN: See Cleaning Preparations and Methods.
LAKES: See Dyes.