For a brazing solder, no other alloy can approach silver solder. It has the advantage of a low melting point, together with toughness, qualities not possessed by the brazing brasses composed of copper and zinc. Such brasses must be high in spelter in order to obtain the necessarily low melting point and they are, there fore, hard and brittle. They do not " flush " as well as silver solder nor give as clean a joint. The melting point of silver is lower than that of copper and as it does not oxidize when heated it is admirably adapted for use in brazing solders. Its cost is the only thing in its disfavor.

The old, time-honored silver solder mixture which is the one so extensively used, consists of:

Fine Silver 2 parts

Pin-Brass 1 part

Pin-brass is supposed to consist of 2 parts copper and 1 part of zinc. As it is difficult to obtain brass scrap that is free from lead, the use of copper and spelter is recommended. The mixeure consists of:

Fine Silver 6 oz. or 66.66 per cent.

Copper 2 oz. or 22.22 " "

Zinc 1 oz. or 11.12 " "

This mixture is called " common silver solder. " It answers for the majority of purposes.

A cheap silver is now sold on the market which gives good results in many operations. It contains less silver than the previous formula. The mixture is as follows:

Fine Silver 3 qz. or 50.00 per cent

Copper 2 oz. or 33.33 " "

Zinc 1 oz. or 16.67 " "

The first mixture has a whiter color than the second. The color of the first mixture is slightly yellow and particularly so when tarnished. Both mixtures roll sheet well or draw into wire.-"The Brass World."