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Description of making Nickel Silver

Nickel silver is an alloy of nickel, copper and zinc. It is used as 'fake silver' or for learning purposes for beginning metalsmithing, as it is cheap. It has a slightly yellowish tinge and is considerably harder than sterling silver. When you are able to melt metals and have a rolling mill, and can obtain the three metals, you can make it yourself. You need moldiing sand (or a metal mold for a blank for rolling sheet), a propane furnace (or electric Kanthal) which is able to reach 1200oC, a graphite crucible and the necessary safety measures to prevent fire from the heat.

Preparation

Work in a well-ventilated room (or outdoors) as some zinc fumes escape from the hot crucible.
The most used composition is 65% copper , 17% zinc and 18% nickel. To get this weigh the three metals in the proper ratios. The nickel should be as fine as possible so that it dissolves easily in the copper zinc alloy. The reason is that the melting point of nickel is 1450oC which can normally not be reached by a propane burner. Copper melts at 1083oC and zinc at a much lower 419oC. After weighing thmetals, put the zinc first into the crucible and cover it with some borax. Put the nickel on top of it and then the copper.
Make a mold from molding sand by putting a ruler into the sand in order to get a casting which can be rolled to sheet. For 20 grams of metal a size of 5x2x0.4cm is suffictent. When you use a metal mold be sure that it is ABSOLUTELY MOISTURE FREE ! Otherwise it explodes when hot metal comes in contact with even tiny amounts (milligrams) of liquid water. Preheat the mold with a burner to just above 100oC.
Then put the crucible in a furnace and heat it until the zinc melts, which should remain under the borax. Then heat it up till yellow-hot (1200oC). Despite the borax some zinc may evaporate and the zinc vapors burn with a bright green flame. The reason is that zinc has a low boiling point (906oC) which is lower than the melting point of copper and even brass.
Now the metal is under a viscous or sticky borax level. Check that everytihing is molten, also the nickel. Pour it into the mold, some bright green flames may appear from the zinc vapors. Remove the sticky borax from the crucible and allow the crucible cool slowly.
Get the metal from the mold and you can quench it in water. Remove all sand and oxides from the metal and now you can roll it to the desired thickness. When it is stretched by 1.5 times its original length it should be annealed to red hot and then quenched in water.
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