When the plating is as heavy as you wish, polish it with a mixture of chalk and alcohol, or of chalk alone, applied with a fine brush, or else a bit of chamois leather or rag.
If you wish to put on a very heavy coat of silver or gold, instead of using zinc alone as a battery, use the following, attach a piece of copper to one end of an iron wire about ten inches long, and a piece of zinc to the other end, and place both zinc and copper in contact with the article being silvered or gilded.
531. USING FRENCH POLISH
There is a mode of using shell-lac varnish which is sometimes denominated the German, but more commonly the French mode. It merits to be generally known, as the process is easy and economical, and the effect beautiful. It has been much employed by cabinet and musical instrument makers, but is not yet so extensively practised as it merits to be. The varnish is applied by means of what is called a rubber, made by rolling up a piece of thick woollen cloth, which has been torn off so as to have a soft, elastic edge. The varnish, put into a narrow-mouthed bottle, is applied to the middle of the flat face of the rubber by laying the rubber on mouth of the bottle and quickly shaking the varnish at once, as the rubber will thus imbibe a sufficient quantity to varnish a considerable extent of surface. The rubber is then enclosed in a soft linen cloth doubled, the remainder of the cloth being gathered together at the back of the rubber to form a handle to hold it by; and the face of the linen cloth must be moistened with a little raw linseed oil, which may either be coloured with alkanet root or not, applied with the finger to the middle of it. The work to be varnished should be placed opposite to the light, in order that the effect of the polishing may be better seen, and a surface of from ten to eight feet square may be varnished at once. The rubber must be quickly and lightly rubbed upon the surface of the article to be varnished, and the rubbing continued until the varnish becomes nearly dry. The coil of woollen cloth must then be again wetted with the varnish, (no more oil need be applied to the surface of the linen cloth,) and the rubbing renewed till the varnish becomes nearly dry as before; a third coat must be applied in the same manner, then a fourth with a little oil, which must be followed by two others without oil, as before. You proceed thus until the varnish has acquired some thickness, which will be after a few repetitions of the series. Apply then a little alcohol to the inside of the linen cloth, and wet the coil with the varnish; after which, rub very quickly, lightly, and uniformly, over every part of the varnished surface, which will tend to make it even, and very much conduce to its polish. The linen cloth must now be wetted with a little alcohol and oil, without varnish; and the varnished surface being rubbed over, with the precautions last mentioned, until it is nearly dry, the effect of the operation will be seen. If it be found not complete, the process must be continued, with the introduction of alcohol in its turn as directed before, until the surface becomes smooth and of a beautiful lustre. The preceding process is that in general use; but Dr. Jones recommends, in the Franklin Journal, a rubber of a different sort, as well as a simpler mode of employing it. He takes a piece of thick woollen cloth, six or eight inches in diameter, and upon one side of this pours a teaspoonful of the varnish; he then collects the edges together, so as to enclose the varnish in the cloth and form a handle by which to hold it: this is finally covered with a piece of oiled linen cloth, and the rubber is ready for use. More varnish is added as often as it is required; and when it becomes occasionally too thick to ooze through, a little alcohol is poured into the cloth. Some difficulties may be at first experienced in performing this process; but Dr. Jones states that a very little practice will enable any handy person to surmount them. The peculiar advantage said to attend it is, that a beautiful polish may be at once obtained by a continued application of the rubber in this way; while, according to the method previously described, successive coats of varnish, which require considerable time to dry, must be used, and a great deal of additional trouble incurred. In varnishing recesses or carved work, where parts of the surface are difficult to reach with the rubber, a spirit varnish, made with or without lac of the usual gum resins, and considerably thicker than that used for the rest of the work, may be applied to those parts with a brush or hair pencil.
532. LACQUER FOR BRASS
Seed-lac, 6 ozs.; amber or copal, ground on porphyry or very clean marble, 2 ozs.; dragon's blood, 40 grains; extract of red sandal-wood, 30 grains; oriental saffron, 36 grains; pounded glass, 4 ozs.; very pure alcohol, 40 ozs. Articles, or ornaments of brass, to which this varnish is to be applied, should be exposed to a gentle heat and then dipped into the varnish. Two or three coatings may be thus applied, if necessary. Articles varnished in this manner may be cleaned with water and a bit of dry rag.
533. TO CLEAN OLD BRASS WORK FOR LACQUERING
First boil a strong lye of wood-ashes, which you may strengthen with soap-lees; put in your brass work, and the lacquer will immediately come off; then have ready a pickle of aquafortis and water, strong enough to take off the dirt; wash it immediately in clean water, dry it well, and lacquer it.
534. TO PREPARE FISH OIL FOR PAINT
Into a cask which will contain about 40 galls., put 32 galls. of good common vinegar; add to this 12 lbs. of litharge, and 12 lbs. of white copperas in powder: bung up the vessel, and shake and roll it well twice a-day for a week, when it will be fit to put into a ton of whale, cod, or seal oil, (but the southern whale oil is to be preferred, on account of its good colour and little or no smell:) shake and mix all together, when it may settle until the next day; then pour off the clear, which will be about seven-eighths of the whole. To clear this part, add 12 galls. of linseed oil, and 2 galls. of spirits of turpentine; shake them well together, and, after the whole has settled two or three days, it will be fit to grind white lead and all fine colours in; and, when ground, cannot be distinguished from those ground in linseed oil, unless by the superiority of colour. If the oil be wanted only for coarse purposes, the linseed oil and oil of turpentine may be added at the same time that the prepared vinegar is put in; and, after being well shaken up, is fit for immediate use, without being suffered to settle. The residue or bottom, when settled by the addition of half its quantity of fresh lime-water, forms an excellent oil for mixing with all the coarse paints for preserving outside work. All colours ground in the above oil, and used for inside work, must be thinned with linseed oil and oil of turpentine.