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Mokume Gane or Woodgrain Metalby Steve Midgett, Earthshine Press Steve Midgett first began working with Mokume Gane in 1974 while apprenticed to a master metalsmith. Since that time he has been a working goldsmith and from 1989 to the present has specialized in one of a kind jewelry incorporating Mokume in it's design. Steve developed the method outlined in this article, presents workshops on Mokume and has recently completed the instructional video "Mokume Gane in a Small Shop". Mokume Gane is an ancient metalworking technique that enables metal artists to produce multicolored sheet stock in a wide variety of patterns. Originally created by Japanese swordsmiths as decoration for their swords, today it is being utilized by designers to create their own distinctive jewelry. The basic technique consists of laminating two to fifty layers of contrasting metals together into one solid billet and then manipulating it to achieve a desired pattern. Many jewelers have tried what is known as the Solder Method to make Mokume, where the contrasting metal layers are sweat soldered together. Although some beautiful things can be made like this it is usually a frustrating procedure that yields marginal results. Laminating wire by this method is the exception. Soldered Wire Mokume Gane
Select two contrasting colored round wires, anneal, pickle and give them a good rub down with steel wool or fine sandpaper. Spot solder just the ends of the wires together, re-clean and secure one end in a bench vice. Tighten the other end into the chuck of a hand drill and begin twisting them together. The tighter and more extreme the twist is the better for this technique. You will probably need to anneal the wire again before you have accomplished a tight enough twist. When done, the wire should look like a section of tightly twisted rope. Flux the entire piece and hard solder the two wires together, using as little solder as possible. Pickle, clean and remove any excess solder. Now roll or forge the piece into a square wire, this will compress the rounded forms of the two individual wires into each other and achieve a solid square cross section. Once again flux the piece, making sure that the flux penetrates into the minute crevices between the compressed wires. Use hard solder to fill these crevices and to create a single square wire. After pickling, remove any excess solder to expose the pattern. This wire may then be flattened into a strip, rolled sideways into a sheet or cut and re-soldered to form a more intricate pattern. However you decide to finish out the piece, the results will be quite striking and are sure to add extra character to your jewelry. Diffusion Welded Mokume GaneThe very finest Mokume is that in which the layers have been diffusion welded together. That is, they have been joined without the aid of solder by the atomic diffusion of one metal into another. By controlling the temperature of the metals and the time they are held in contact, one can control this diffusion very accurately and achieve a seemingly invisible yet permanent bond between the layers. The Japanese swordsmiths did this by binding the metals very tightly with heavy wire between two sheets of steel and "firing" the billet in a blacksmiths forge. The forge not only provided a steady even source of heat, but by its very nature created a reducing or oxygen starved atmosphere. The reducing atmosphere is critical, because oxygen inhibits proper bonding. The Mokume Kiln
The kiln is made out of two standard sized soft fire bricks and is fired by your jewelry torch. It has five main parts: the Firing Chamber, the Burner Port, the Spy Hole and Secondary Burner Port, the Clamp Recess and the Frame. Also, a billet clamp and a steel clamp plate. Metals for MokumeThe gold alloys which work best in a Mokume laminate are Hoover & Strong's 18K green, 22K yellow and 14K palladium white gold. All of these have very good fusing characteristics and work well in the finished laminate. The color of the yellow golds are rich and the 14K palladium white is the only white gold that will work for Mokume. Silver alloys include sterling, fine and reticulation silver depending on which characteristic of color or hardness you wish to exploit. Copper alloys suitable for Mokume include pure copper, brass and nickel silver. One of my favorite alloys for Mokume is a traditional Japanese alloy known as Shakudo. It contains 2% to 15% fine gold with the balance being copper. This alloy naturally patinas to a rich brown, dark purple or black. Firing the BilletWhen you have selected the metals you wish to use in your Mokume laminate, they must first be flattened and thoroughly cleaned. After cleaning they are stacked in their proper order and clamped, with a heavy C clamp, very tightly together between two clamp plates. Great care must be taken to assure that the surface of the sheets are clean and make total contact with each other, or else diffusion will not occur. The whole clamp assembly is then loaded into the kiln and fired to the appropriate temperature using a torch for the kiln burner. After firing, the welded billet is removed from the kiln, lightly forged and rolled to the desired thickness. PatterningThere are as many different patterns that can be achieved with Mokume as there are individuals who make it, but the most basic technique that yields an infinite variety, is known as the Punch Method. After reducing the billet to the desired thickness, the sheet is embedded face down into a pitch bowl. Using chasing tools a design is then punched down into the sheet. The depth of the punch marks should not exceed 50% of the sheet thickness. After all the punching has been done the sheet is removed from the pitch and the resulting bumps on the front side are filed back to the surface level of the sheet. Filing off the raised bumps and ridges cuts through and exposes some of the sheets internal layers. This creates the Mokume pattern. By controlling punch patterns, metal colors and thicknesses, patterns resembling woodgrain, geometric lines, bulls eyes, animal skins or any combination of the above can all be created. Whatever you decide to create using Mokume Gane, you will find it a rewarding technique to use and one which is sure to give your jewelry a distinctive and personal look. Copyright © by Steve Midgett 1995 [_PRIVATE/bottom.htm] |
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