A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century A.D. v1.c18.s1: Soldering
A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century A.D. v1.c18.s1
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Soldering
v1.c18.s1.1
The next process that we shall consider is soldering. This is undoubtedly the most important process that the goldsmith has to perform from a commercial point of view. It is in the course of this process that the practical goldsmith plays those mischievous tricks which go so hard against those who purchase his productions or order for them. The quality or quantity of solder (or *pān*) employed is the first question that is universally enquired into in all cases of commercial dealings in Indian jewelry; and while by melting some articles the value of the gold per tola is reduced by Re. 1 or 2 only, we frequently find cases in which the value is decreased at the ruinous rate of Rs. 8 or Rs. 10. This last state of affairs arises when the solder consists almost entirely of a mixture of baser metals and is at the same time fraudulently used in larger quantities than what is absolutely necessary.
v1.c18.s1.2
Considered, however, from the standpoint of a chemical student who investigates the subject of ascertaining the amount of metal that is lost in the operations of the goldsmith, the process of soldering is scarcely important enough to receive a separate treatment. The preparation of the solder and its reduction to the condition of small thin bits are embraced in the discussion of melting and hammering; while the loss during the blowing operation, during which the reducing flame of an oil lamp is made to play upon the solder and the parts it is meant to join together, may be supposed to have been treated during the discussion of the subject of loss of gold by volatilisation. The fact that almost all solders contain a little zinc perhaps makes the loss in their case to be much greater than in that of an alloy of gold and copper only. The following three sets of figures give the weight of gold and the weight of solder before the process of soldering and the weight of the article after the operation has been finished :—
v1.c18.s1.3
| Gold | Solder | Wt. of Gold & Solder after operation. |
| Tolas annas pies. | Tolas annas pies. | Tolas annas peis |
| 6 0 0 | 1 0 0 | 6 15 0 |
| 2 0 0 | 0 8 0 | 2 7 13/4 |
| 3 8 0 | 1 4 0 | 4 10 3 |
v1.c18.s1.4
Thus, on the whole a loss of 11 1/4 pies takes place in dealing with 14 1/4 tolas of materials. This gives the rate of loss at .79 pies per tola.
v1.c18.s1.5
It is proper to observe that of the loss that takes place during soldering, about one-third is due to purely physical causes, *e. g.* the loss of pieces of solder which fly off before the blowpipe. The above figures are accordingly not to be supposed as affording an accurate estimate of the amount of material that is lost by vapourisation during the operation of soldering.