Creating Mokume Gane (page 1 of 3)

Mokume Gane:
Manufacturing Works of Art

by Mark B. Mann

technical contributions by James Binnion
of James Binnion Metal Arts LLC, Bellingham, WA

First published in Professional Jeweler magazine,
an international jewelry trade publication

Photos by Mark B. Mann; header photo
and photo #8 courtesy James Binnion

	As you've likely read on preceding pages, mokume gane—translated from the Japanese—means "wood eye metal." Japanese craftsmen developed this rare metal lamination process in the 17th century for the adornment of samurai swords ... and today, mokume gane jewelry is growing in popularity. This article covers the details related to the design and manufacturing process.

The Layering and Bonding Process

The mokume gane process begins by layering and bonding several sheets of two to four different metal alloys. The sheets can be joined using solder or fusion bonding. This overview describes a solder-free solid-state diffusion bonding method developed and used by James Binnion.

1. The materials used for this mokume gane manufacturing overview are alternating sheets of 14-karat palladium white gold and sterling silver. Each sheet of metal is approximately 1.5 millimeters thick.

2. Chipp Allard, Binnion's assistant who studied at the Revere Academy of Jewelry Arts, San Francisco, meticulously cleans the sheets by placing them in a holding spring in a plastic bowl. He adds Tiva cleaning solution, then holds the bowl in an ultrasonic cleaner.

3. Allard sands the sheets individually, using a three-step abrasive process. After completing the abrasive procedure, he rinses the sheets, blows them with nitrogen to dry them, and places them in a vacuum chamber to pull off any remaining water vapor.

4. Binnion places the cleaned sheets (indicated by the arrow) in a torque plate in preparation for compression. The torque plate is positioned in a hydraulic press, and the sheets are compressed mechanically. Binnion says that compression creates "intimate contact" between layers.

5. The torque plates with the compressed metal are placed into a container and then covered with hot powdered charcoal. The container is capped and lowered into the kiln for diffusion bonding. Time and temperature for bonding depends upon the alloys. After the bonding is complete, the torque plates and metals are allowed to cool. The newly bonded metal, now referred to as a billet, is removed from the torque plates.

6. Next, Binnion reduces the thickness of the billet by 30 to 60 per cent, a step that also increases the integrity of the bond. To do this, he heats the billet to annealing temperatures in a small furnace, places it in a heavy drop hammer, and quickly hits the foot pedal. The hammer drops and compresses the billet. He repeats this process several times to obtain the required reduction.

7. The billet is cut into bars, then twisted and rolled round. The rounded billet is forged in the hydraulic press in preparation for the jewelry - in this case, a comfort fit band.

Creating the Pattern

8. The next step - patterning - involves creating the pattern of bonded metals around the band. In this example, the yellow, red and palladium white gold pattern resembles wood grain. Patterns are accomplished by repeating a multiple step process of high speed carving, de-burring, forging and shaping. This is where Binnion's true artistry comes into play in creating his unique mokume gane jewelry. Notice that the pattern is visible from the top and inside views of the band.

9. To create the mokume gane pattern, Binnion first uses a high-speed 1/2-horsepower turbine air tool with a carbide bit, running at 45,000 rpm, to carve indentations into the billet.

NEXT (page 2 of 3) PAGE 3 MAIN MOKUME PAGES

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