SOLDER is the name of a metallic compound, used to join together other metals. The following are some of the most important of the solders, it being a general principle that some of the metals to be sol dered should be mixed with some higher and liner metals.
1. Solder for gold consists of fine gold, with one fourth or one-half its weight of line silver, mixed by fusion, and beat out into leaves thinner than card paper, and rendered soft by annealing. A portion is then laid on the fracture, or ends to be united, and it is sprinkled with pulverized borax. The flame of a blow-pipe is then used to melt the whole. The borax is removed by boiling water, or a little dilute sulphur ic or muriatic acid; and the paler colour of the solder may be deepened, by melting on its surface a mixture of two parts of nitre, and one of burnt alum, and washing it off with hot water. Silver after solder ing, may be cleansed by boiling it in alum water, and gold by urine and salammoniac.
Solder for gold may also be made with gold and a little copper.
2. Solder for Steel and with a slight alloy of copper is a good solder for uniting the finer kinds of steel instruments. For larger articles in iron and steel, an alloy of equal parts of tin and iron is used.
3. Solder for Plumbers.—This solder consists of two parts of lead, and one of block tin. It is known to be good when small bright shining stars rise in a small piece of it poured out of the crucible in which it is melted. Equal parts of lead and tin are used when it is wished to be hard; and when it is wanted to be very fusible, bismuth is added in various pro portions. •
4. Solder for hard kind is composed of equal parts of silver and fine brass, and the soft is made by fusing the hard solder with one-sixteenth its weight of pure zinc.
A second solder for silver is made of two parts of fine silver, and one of brass, which must not be kept long in a state of fusion, lest the brass be oxidated.
A third solder for coarser silver is made of four parts of fine silver, three of brass, with a little borax, and it must be poured out when melted.
5. Solder for copper. This is made of copper and tin; but for line work silver is substituted for tin.
6. Solder for copper, brass, and the hard alloys of copper. The best hard solder for these purposes is made of brass and zinc, from eight to sixteen parts of brass to one of zinc, according to the hardness re quired. The soft olde• consists of three parts zinc and one lead, and is applied by a common red hot soldering iron.
7. Solder for organ pipes. This is made of three parts pewter and one bismuth.
8. Soft pewterer's solder, is composed of two parts tin and one bismuth, which is very easily melted.
9. Speller solder. This is made of two-parts of speller, (the commercial name for zinc,) and one of brass. It is used by braziers and coppersmiths for brass, copper, and iron. A dwt. of silver to each oz. improves it greatly.