For Britannia metal a solder is used consisting of 1 part lead and 2 parts tin, with resin or chloride of zinc as a flux. The proportion of soft solder is made by first melting the tin in either a porcelain or stone vessel. After it has been melted the lead is added in small proportions and the combination of the two metals is effected by stirring with a stick of wood. The alloy is then to be poured into molds, one of the best shapes being 7 3/4 inches long and l 1/2 inches high and 1/8 to 1/4 inch thick.
(2) A solder for Britannia metal is composed as follows: Tin. 8 parts; lead, 4 parts; bismuth, 1 part. Melt at a moderate heat and run into bars.
The composition of solders for. aluminum that are generally used is as follows:
(2) 88 parts Zinc. 7 parts Aluminum, 5 parts Copper.
(3) 94 parts Zinc, 4 parts Aluminum. 2 parts Copper.
(4) 90 parts Zinc. 6 parts Aluminum, 4 parts Copper.
(5) 85 parts Zinc, 9 parts Aluminum, 6 parts Copper,
First prepare an aluminum copper alloy which is to be mixed with the requisite amount of zinc. Melt the copper and then gradually introduce into same the aluminum, divided into 3 or 4 portions; make a perfect mixture by stirring. After the last of the aluminum has been put in, throw in the zinc and with it some fat or resin, then stir the mass rapidly and directly remove the crucible from the fire and pour the alloy into iron molds, which have been rubbed with benzine or cold tar oil.
A good aluminum solder is made of zinc, aluminum and copper, in the proportion of 90, 6 and 4.
(2) A second solution is composed of 6 44-100 per cent. Copper, 4 68-100 per cent. Silver, 88 88-100 per cent. Gold.
A solder for German silver is composed of the following: German silver, 5 parts: pure zinc, 4 parts. German silver used is made of: Copper, 8 parts; nickel, 2 parts, and zinc, 3.5 parts.
To make a good solder for glass make an alloy of 95 per cent. tin and 5 per cent. zinc.
The best solder for uniting gold is made by melting 66.6 parts gold with 16.7 copper, and 16.7 silver. This alloy is a firm and easily working solder, though a very good solder for gold for general purposes is made by adding to 100 parts gold, 40 of silver, and 30 of copper.
A solder for hard brass is composed of the following: Scraps of metal to be soldered, 4 parts; zinc, 1 part.
For the finer kinds of iron and steel instruments gold is an excellent solder, as it possesses the power of dissolving iron in a degree of heat far less than is required for melting iron. Therefore, if a small plate of gold is wrapped round the parts to be joined, and then melted with the blow-pipe, it strongly unites the parts together without any injury whatever to the instrument, however delicate.