ENAMELLING, the art of covering thin plates of metal with the substance called enamel. As this curi ous art is carried on to a considerable extent among the manufacturers of watch dial plates, we shall give our readers a general idea of the art of enamelling, by ex plaining the nature of their manufacture.
Dial Plate Manufacturing.
Dial plate making is divided into hard enamelling, in which the surface of the plate is covered with hard or Venetian enamel ; and into glass or soft enamelling, in which the surface of the plate is covered with the English soft glass enamel, which is always considered much in ferior to hard enamelling.
The metals that suit this kind of enamelling best, are fine gold or fine copper ; the former may be had from any goldsmith, the latter at the flatting mills, known by the name of enamellers copper. It is necessary to cau tion persons unacquainted with the art against using the copper too thick, as, in that case, the plates would crack in the fire.
The slips of copper being cut into square pieces, put them into a clear fire, till they have attained a red heat ; when cold they are formed into the intended shape of the dial. Before proceeding, however, to explain this pro cess, we shall here introduce a description of the tools required in the operation.
1st, The dies are small circular plates of brass, about of an inch thick. Their edges should be turned a little conical, and in their centres should be holes near ly as large as those to be made in the dial plates. .An enameller ought to have at least forty of these, from iths of an inch, up to 2 inches diameter, observing that the gradation from one size to another should be exceeding ly small, having three sizes between every division on the gauge. See Fig. I. of Plate CCLII.
2d, A round ended punch made of steel wire, about of an inch thick and 11 long. This should be fixed in a convenient handle, and is then fit to punch up the copper into the centre holes of the dies. Sde Fig. 2.
3d, A clock maker's round broach. This should be firmly fixed into a strong handle, being used to burnish up an edge to the copper, and likewise to square up the centre holes. See Fig. 3.
4th, A die or block, to set the copper of the desired concavity. This should be turned of box or any other hard wood, and should be a little larger in its diameter than the largest brass die. This must have a hole through the centre something wider than the hole in the dial plate. See Fig. 4.
5th, A large pair of scissars to cut the copper with. Horse scissars are most proper for this purpose.
6th, A setting spatula, which should be made of steel wire, about Adis of an inch in diameter and 5 inches long. One end of this should be beat flat and thin. The end so prepared is then to be filed a little round, and the flat part bent so as to form a segment of a circle, some what smaller than the curve of the setting die. The outer part of the curve should then be smoothed on an oil stone, and the tool is fit to be used. See Fig. 5.
7th, A smooth needle maker's file, used for filing the plated wire, which will be -hereafter explained, and like wise the edge of the copper, after it has been burnished up to the edge of the brass die.
8th, A small steel point, which should be rather stout er than a stocking needle, used for marking the place where the feet of the dial should be put, and other pur poses to be described. See Fig. 6.
9th, A large soldering lamp, which should hold at least a quart of oil. This must have a cylindrical spout for the cotton, at least one inch and a quarter in diame ter, that the oil may have free access to the lighted end of the cotton. See Fig. 7.
10th, A pair of corn tongs, or tweezers. These are so well known as to need no description.
th, A blow pipe for soldering the feet upon the cop pers, of a convenient length, and the hole a little more open than for other purposes.
12th, A watchmaker's glass and dial gauge. See Fig. 8.