Mokume Gane - translated from 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. The article below details the labor-intensive process.
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 © Visual Communications Inc. - Photos by Mark B. Mann; photo #8 courtesy James Binnion
I. 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.
(you can really see the time, effort, and artistry that is required to create these pieces...not to mention the passion and dedication that is necessary to undergo such an all-consuming process.)
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.
In the next section, you will understand more about how the actual patterns are created....
II. 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 starts out by using a high-speed 1/2-horsepower turbine air tool with a carbide bit, running at 45,000 rpm, to carve indentations into the billet.
10. After carving and deburring the billet, Binnion inserts it into a custom-made ring-forming die and places it in a hydraulic press to be forged. Forging flattens the carved billet, ultimately creating the unique pattern. This photo shows the billet after several repetitions of carving, de-burring and forging.
III. Forming the Ring and Sizing
11. The billet started out measuring 8.25 millimeters in width, and needs to be 6.5 millimeters when completed. So final shaping and forming will be done with custom-made dies and a rolling mill.
12. Allard then takes the ring blank and cuts it to length to fill the order. He uses an adapted vise to hold the billet for sawing.
13. The ring blank billet is placed into a tube furnace for annealing. Argon flows into the chamber, creating an inert atmosphere and limiting oxidation. When completed, Binnion pulls the blank out of the furnace and it drops into water.
14. To form the ring, he uses a bending device with custom-made forming jigs. The Delrin jigs eliminate excessive tool marks.
15. Allard shapes the ring and adjusts the alignment and prepares it for soldering.
16. Soldering is done at a special station. The hardest possible solder is used, allowing leeway for future alterations on the ring. The ring is fire-coated with a mixture of boric acid and denatured alcohol. Because the different metals expand and contract at different rates, it is necessary to "confine" the ring with a custom holding device during the heating process.
IV. Finishing and Examples
All that's left is the finishing. Binnion uses a variety of finishes on his pieces, but his favorite is a matte, which highlights the contrasting metal colors. He often uses an etched finish on pieces containing silver. Here are some examples of his designs, patterns and finishes.
17. This pattern is referred to as a "tight star," and has a matte finish. The metals are 18-karat yellow gold, 14-karat palladium white gold and 14-karat red gold. The ring has a platinum liner and rails.
18. This 6-millimeter comfort fit with a "tight star" pattern has a beautiful etched finish. The metals are 14-karat palladium white gold, 14-karat red gold and sterling silver.
19. This ring is 6 millimeters wide, with a "tight wood grain" pattern.
The metals are 18-karat yellow gold, 14-karat palladium white gold and sterling silver. The center stone is a Mandarin garnet; the side stones are green diamonds - all set in 18-karat yellow gold bezels.
This ring is a great example of how your own stones (or ones you would like to acquire) can be custom set for you.
V. Rails and Liners
Rails and liners are, respectively, edge-trim pieces and the inside solid flat surface (using a single alloy) for mokume gane bands. They are optional features on James Binnion's mokume gane bands. Here are some examples of how his products are offered:
20. This band has no rails or liner; the mokume gane pattern is visible from all views.
21. This ring has yellow gold rails. The rails provide a single-color design element on both sides, essentially framing the mokume gane pattern that's visible on the top and inside the ring.
22. This band has yellow gold rails and a liner. The pattern is visible from the top. The liner enhances engraving possibilities on the inside of the band, making it easier to read.
Occasionally certain individuals may have a sensitivity to one or more of the metals in a mokume gane laminate; the liner (made of gold or platinum) inhibits direct and constant contact with those alloys, and this can alleviate the sensitivity issue.
VI. Installation Techniques for Liners
23. This palladium white gold and sterling silver mokume gane band is being prepared for a 14-karat palladium white gold liner.
Here it is mounted in a lathe, and the cutting tool will create a flat surface inside the band.
24. The inside edges of the shank are chamfered. The palladium white gold liner is made to specifications and after precise fitting, it's inserted and mechanically pressed into the band. It's then flared on each edge.
25. Beads of 14-karat white gold easy solder and flux are carefully placed around each side of the band. A hot air gun is used to dry the flux, which holds the beads in position for soldering.
The band is placed on a custom stand and soldered.
VII. Installation Techniques for Rails
26. For this palladium white gold and sterling silver mokume gane band, grooves are cut on the sides and 14-karat palladium white gold rails are fit precisely. The rails are wired to each side and the band is prepared for soldering.
27. Beads of 14-karat white gold easy solder are evenly placed around the seam between the rail and the band. A hot air gun is used to dry the flux and to secure the beads of solder. The ring is placed on a custom stand and soldering is completed.
And THAT is a basic lesson about how Mokume Gane is manufactured!
Here's a great video on a website called Ganoskin: BenchTube.
Prepare to be amazed as you watch the process of creating Mokume Gane jewelry!
