Soldering is a process which, by means of a more fusible compound, the connecting surfaces of metals are firmly secured to each other, but, for many practical purposes, it is advisable to have the fusing point of the metal and solder as near each other as possible, which, in the majority of cases, preserves a union more lasting, and the joint less distinguishable, in consequence of the similarity of the metal and solder in color, which age does not destroy, and this is not the case with solders the fusible points of which are very low. The metal to be soldered together must have an affinity for the solder, otherwise the union will be imperfect; and the solder should likewise act upon the metal, partly by this affinity or chemical attraction, and partly by cohesive force, to unite the connections soundly and firmly together. Solders should therefore be prepared suitable to the work in hand, if a good and lasting job is to be made. It should always be borne in mind that the higher the fusing point of the gold alloy —and this can be made to vary considerably, even with any specified quality— the harder solder must be used, for. in the case of a more fusible mixture of gold, the latter would melt before the solder and cause the work to be destroyed. A very good formula for the first,  or ordinary, 22-carat alloy is this:

dwts.      grs.

Fine gold........... 1         0

Fine silver.......... 0        3

Fine copper......... 0         2

1         5

This mixture will answer all the many purposes of the jobber; for soldering high quality gold wares that come for repairs, particularly wedding rings, it will be found admirably suited. If an easier solder is wanted, and such is very often the case with jobbing jewelers, especially where several solderings have to be accomplished, it is as well to have at hand a solder which will not disturb the previous soldering places, for if this is not prevented a very simple job is made very difficult, and a lot of time and patience wholly wasted. To guard against a thing of this kind the following solder may be employed on the top of the previous one:

dwts. grs.

Fine gold........... 1         0

Fine silver.......... 0         3

Yellow brass........ 0        2

1         5

This solder is of the same value as the previous one, but its melting point is lower, and it will be found useful for many purposes that can be turned to good account in a jobbing jeweler's business.

JEWELERS' ALLOYS:

See also Alloys and Solders.

18-Carat Gold for Rings

Gold coin, 19.5 grains; pure copper, 3 grains; pure silver, 1.5 grains.

Cheap Gold, 12 Carat

Gold coin, 25 grains; pure copper, 13.5 grains; pure silver, 7 and 1/3 grains.

Very Cheap 4-Carat Gold

Copper, 18 parts; gold, 4 parts; silver, 2 parts.