Mokume-gane

Mokume-gane, or mokume damascus, is simply damascus metal made from of non-ferris metals like gold, silver, and copper.

In 17th century Japan, a master maker of sword-fittings named Denbei Shoami developed a method of laminating and patterning precious and semiprecious metals. He called his invention "guri bori" because of its semblance to the carved laquer art or "guri." He later changed the name to "wood-burl metal" or "mokume gane." Other names given to his product were kasumi-uchi, itame-gane (wood-graine metal), or yosefuki.

The traditional semi-precious alloys used are Shibuichi and Shakudo. Shakudo is a alloy of 95% copper and 5% gold. Shibuichi is make of 75% copper and 25% silver. Kuromi-do is the third alloy, made of 99% copper and 1% arsenic. Because of the arsenic it cannot be made safely indoors. Other materials it can be made of are fine silver, sterling silver, gold, copper, brass, nu-gold (a copper/zinc alloy, also called jewlers bronze), nickel silver (a copper/nickel alloy, also called German Silver) and pure nickel.

Polymer art-clay enthusiasts will also refer to similar patterns of layered clay as "mokume gane."

A modern small batch method for making mukume-gane

The metal of the layers must be absolutely clean, there can be no dust, dirt, grease, or anything else. You need torque plates to make it. The torque plates are basically two steel plates with bolts in the corners that allow the two plates to be forced together. Paint the insides of the steel plates with yellow ochre, or Scalex to prevent them from laminating to the billet. You tighten the plates together as tightly as you can, put it under a hydraulic press, squash everything together as tight as you can, then tighten the bolts again.

Put the torque plates in a thin steel plate (no thicker than 28 gauge) or a stainless steel foil wrap bag, along with some charcoal to get rid of any oxygen, and put then entire thing in a preheated furnace (temperature must be 50 to 100 degrees fahrenheit beneath the lowest melting point in the stack) and keep it in there for three to twelve hours. After this time remove the billet from the furnace and torque plate, and while it is still hot start forging it. A billet with silver in it must be forged at 'black heat', or when the billet isn't glowing red. Cool billet and saw about 1/8 to 1/4 of an inch of the edges of the billet to prevent stress cracking. Heat the billet with a torch and continue forging. At this point you can start a pattern development using burrs, drills, files, punches, chisels, and mills. Anneal with borax often.

Coloring

To color the shakudo and gold, submerse the piece in boiling rokusho, and hold there--agitating constantly--until it reaches the desired color. Rokusho colors shakudo a black-purple. The more gold is in the alloy the more purple it turns. Rokusho is made in Japan but can not be found in the United States. Rokusho is a solution of 6 g cupric acetate, 1.5 g copper sulphate, table salt in 1 L of distilled water.

Some people used a paste made of ground daikon radish. The recipe is the following; 1 part Daikon radish to 5 parts water, ground with a mortar and pestle.

The paste is applied immediately before the piece is boiled in the rokusho to protect the surface against tarnish and uneven coloring. After the coloring process is over, the finished piece is waxed.

External links

http://aslanzephirine.com/ good examples of mokume-gane from master goldsmiths