Henley's Twentieth Century Formulas, Recipes and Processes. Various
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and is in many cases so thin that hard rubbing will bring through the color of the base. Such articles, of course, are not durable. In genuine talmi gold, the coating, even though it may be thin, adheres very closely to the base, for the reason that the two metals are actually welded by the rolling, and also because alloyed gold is always used, which is much harder than pure gold. The pure gold of electroplating is very soft. The composition of some varieties of talmi gold are here given. It will be seen that the content of gold varies greatly, and the durability of the alloy will, of course, correspond to this. The alloys I, II, III are genuine Paris talmi gold; IV, V, and VI are electroplated imitations; and VII is an alloy of a wrong composition, to which the gold does not adhere firmly:
| Copper | Zinc | Tin | Iron | Gold | |
|---|---|---|---|---|---|
| I. | 89.9 | 9.3 | — | — | 1.3 |
| II. | 90.8 | 8.3 | — | — | 0.9 |
| III. | 90.0 | 8.9 | — | — | 0.9 |
| IV. | 90.7 88.2 | 89.0 11.4 | — | — | 0.5 |
| V. | 87.5 83.1 | 12.4 17.0 | — | — | 0.3 |
| VI. | 93.5 84.5 | 6.6 15.8 | — | — | 0.05 |
| VII. | 86.0 | 12.0 | 1.1 | 0.3 | — |
Japanese Alloys.
—In Japan some specialties in metallic alloys are in use of which the composition is as follows:
Shadke consists of copper with from 1 to 10 per cent of gold. Articles made from this alloy are laid in a pickle of blue vitriol, alum, and verdigris, until they acquire a bluish-black color.
Gui-shi-bu-ichi is an alloy of copper containing 30 to 50 per cent of silver. It possesses a peculiar gray shade.
Mokume consists of several compositions. Thus, about 30 gold foils (genuine) are welded together with shadke, copper, silver, and gui-shi-bu-ichi and pierced. The pierced holes are, after firmly hammering together the plates, filled up with the above-named pickle.
The finest Japanese brass consists of 10 parts copper and 8 parts zinc, and is called siachu. The bell metal kara kane is composed of copper 10 parts, tin 10 parts, iron 0.5 part, and zinc 1.5 parts. The copper is first fused, then the remaining metals are added in rotation.
German Silver Or Argentan.
The composition of this alloy varies considerably, but from the adjoined figures an average may be found, which will represent, approximately, the normal composition:
| Copper | 50 to 66 parts |
| Zinc | 19 to 31 parts |
| Nickel | 13 to 18 parts |
The properties of the different kinds, such as their color, ductility, fusibility, {70} etc., vary with the proportions of the single metals. For making spoons, forks, cups, candlesticks, etc., the most suitable proportions are 50 parts of copper, 25 of zinc, and 25 of nickel. This metal has a beautiful blue-white color, and does not tarnish easily.
German silver is sometimes so brittle that a spoon, if allowed to fall upon the floor, will break; this, of course, indicates faulty composition. But the following table will show how the character of the alloy changes with the varying percentage of the metals composing it:
| Copper | Zinc | Nickel | Quality | |
|---|---|---|---|---|
| I. | 8 | 3.5 | 4 | Finest quality. |
| II. | 8 | 3.5 | 6 | Beautiful, but refractory. |
| III. | 8 | 6.5 | 3 | Ordinary, readily fusible. |
| IV. | 52 | 26.0 | 22 | First quality. |
| V. | 59 | 30.0 | 11 | Second quality. |
| VI. | 63 | 31.0 | 6 | Third quality. |
The following analyses give further particulars in regard to different kinds of German silver:
| For sheet | Copper | Zinc | Nickel | Lead | Iron |
|---|---|---|---|---|---|
| (French) | 50.0 | 31.3 | 18.7 | — | — |
| (French) | 50.0 | 30.0 | 20.0 | — | — |
| (French) | 58.3 | 25.0 | 16.7 | — | — |
| Vienna | 50.0 | 25.0 | 25.0 | — | — |
| Vienna |
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