Procedures for Melting Silver & Gold

Removing Impurities

• Most gold and silver contains impurities that need to be removed. A compound, called "flux," needs to be placed over the metal before heating. Any impurities are drawn into the flux, which sits suspended above the metal. The flux is poured into the mold with the metals but remains separate, so it can be removed when the metal is cooled. The more impurities there are, the more flux is required. Even if the metal appears to be relatively free of impurities, some flux is necessary. One easy way to make flux mixture is to combine borax with sodium carbonate. This is ideal for melting cleaner gold, such as jewelry scraps. Use about two pinches of flux for every ounce of jewelry gold, and four pinches for dirty scrap gold. Putting the flux on top of the gold prevents gold particles from blowing away when heat is applied by a blowtorch.

Heat

• Pure gold melts at 1,060 degrees Celsius or 1,940 degrees Fahrenheit. However, this temperature may decrease if other metals, such as silver or copper, are alloyed with the gold. For example, 14 karat gold melts at about 1,650 F on average. Silver melts at about 200 degrees below the temperature for gold. Melt the gold in a crucible made of graphite carbon rather than a ceramic one, because heated flux tends to eat through ceramic. Crucibles are available at jewelry supply stores.

Torch

• Place the gold or silver, covered by the flux, in the crucible. Ignite either an oxyacetylene or oxygen-propane torch. If you are melting dust or filings, lower the torch slowly into the crucible; bringing it down too fast can blow away fine gold, such as gold dust. Also, heating the crucible too fast may crack it. The torch should gently melt the top layer so that it spreads out and protects the gold below it.

Kiln

• As an alternative to a blowtorch, heat an electric or gas-fired kiln to the temperatures needed for melting gold or silver and place the crucible plus the metal in it. When the metal has melted, you must remove it quickly from the kiln or crucible. Typically, you would use long tongs to do this. The metal then needs to be poured into a mold to set. During the melting process, anyone working with the metal must wear protective goggles and gloves. Splashing metal causes severe skin burns.