The solders which contain silver are very strong and tenacious, and are used not only to solder silver, but also for other metals, in cases where the objects to be soldered require great power of resistance. Two principal kinds of silver solder are distinguished, hard and soft, the former consisting of silver and copper, with sometimes a little zinc, and the latter containing, besides the metals just mentioned, a small amount of tin.

Hard Silver Solder

According to the purpose for which this is intended, different compositions are used varying in fusibility. Silver workers use different solders for alloys of varying degrees of fineness, and the same ones are not always employed for re-soldering as for the first soldering.

Silver Solders Very Hard (For Fine Silver Articles)

Copper ................................... 1

Silver .................................... 4

Hard

I.

Copper ................................... 1

Silver .................................... 20

Brass .................................... 9

11.

Copper ................................... 2

Silver .................................... 28

Brass .................................... 10

Soft

I.

Silver.................................... 2

Brass .................................... 1

II.

Silver .................................... 3

Copper ................................... 2

Zinc ..................................... 1

III.

Silver .................................... 10

Brass .................................... 10

Tin ...................................... 1

These solders serve principally for completing the soldering of silver articles done with hard solder, by retouching imperfect places. Some silver workers use for this purpose copper and silver alloys mixed with zinc, as for example, the following:

Copper ................................... 4

Silver .................................... 12

Zinc ...................................... I

Or,

Silver .................................... 5

Brass ..................................... 6

Zinc ...................................... 2

The latter is readily fusible, but also rather brittle, and is frequently used for soldering ordinary silverware.

Solders For Iron, Steel, Cast Iron, And Copper

I.

Silver .................................... 10

Brass .................................... 10

II.

Silver .................................... 20

Copper ................................... 30

Zinc ..................................... 10

III.

Silver ..................................... 30

Copper ................................... 10

Tin ...................................... 0.5

Soft Silver Solder

Silver .................................... 60

Brass ..................................... 60

Zinc ..................................... 5

In the case of soiders which are prepared with brass, care-should be taken that neither of the metals in the composition contains iron, as it has been found by experience that the presence of a very trifling amount of this is sufficient to change the character of the alloy materially, making it brittle.

Silver solders are used in the form of fine filings or wire, the latter method of preparing it being especially adapted to the tenacious and ductile nature of the alloy.

In the large manufactories for silver ware it has become the custom in recent years to use the same alloy for soldering as that of which the silver article is made. It is used in the form of filings, and melted into the seams so that the object and the solder are really homogeneous.