3488. Hard Soldering or Brazing

3488.    Hard Soldering or Brazing. The alloy used in hard soldering is generally made of equal parts of copper and zinc; much of the zinc, however, is lost in the process, so that the real proportion is not equal parts. The alloy is heated over a charcoal fire, and broken to granulations in an iron mortar. A different proportion is used for soldering copper and iron, viz.: 3 zinc to 1 copper. The commercial name is "spelter solder."

3489. Flux for Spelter Solder

3489.    Flux for Spelter Solder. The flux employed for spelter solder is borax, which can either be used separately, or mixed, by rubbing to a cream, or mixed with the solder in a very little water.

3490. To Hard Solder

3490.     To Hard Solder. When the work is cleaned, bound, fluxed, and speltered, the whole is subjected to a clear charcoal or coke fire; or, what is now becoming far more general, convenient, cleanly, and manageable, a bellows blowpipe. The air passes from a bellows propelled by the foot through A (See Engraving.) The gas passes through B,

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and the flame can be directed to any point, on account of its being hinged at C C. The flame can be extended by using several stands, or by constructing several burners on one stand. The heat is much greater than from charcoal, can be regulated at pleasure, and kept at the same temperature for any given time. In the process of hard soldering, the water should be driven off by gentle heat; the fusion of the flux soon follows; a glassy substance appears after the froth, which, in its turn, is replaced by the alloy in red liquid form; the blue flame from the ignited zinc informs the operator that the solder now fuses, so that, as soon as the work is flushed with solder, it must be withdrawn, allowed to set, and cooled in water.

3491. To Make Solder

3491.    To Make Solder. The mixture of the metals is performed by melting them together in the same manner as for alloys (see No. 3347), with the aid of a flux. The metals employed should be pure, especially silver, as silver coin makes the solder too hard.

3492. Solder for Gold

3492.    Solder for Gold. Take 12 parts pure gold, 2 parts pure silver, and 2 parts copper.

3493. Solder for Silver

3493. Solder for Silver. Take 5 parts pure silver - not silver coin - 6 parts brass, and 2 parts zinc. Or, 2 parts silver, 1 part common pins. This is an easy flowing solder. Use a gas jet to solder with.

3494. Hard Solder

3494.    Hard Solder. Take 2 parts copper and 1 part zinc. Or, equal parts of copper and zinc. (See No. 3488 (Hard Soldering or Brazing).)

3495. Solder for Silver

3495.     Solder for Silver. Take 19 parts fine silver, 1 part copper, and 10 parts brass.