Professional Jeweler Archive: Mokume-Gane: Manufacturing Works of Art, Part 1

October 2004

Professional Bench/Defining Quality


Mokume-Gane: Manufacturing Works of Art, Part 1

Knowing how mokume-gane is accomplished demonstrates another aspect of quality in your shop


Mokume-gane translated from Japanese means “wood eye metal.” Japanese craftsmen developed this rare metal lamination process in the 17th century to adorn samurai swords. Today, mokume-gane jewelry is growing in popularity. This article covers details of the manufacturing process, illustrated by James Binnion’s mokume-gane rings. Next month, Part 2 will look at other features, including ring liners and rails, settings, servicing and quality issues.
This 9mm mokume-gane wedding band contains 14k palladium white and sterling silver. It is a comfort-fit wedding band with 18k yellow gold millgrain rails and a liner. It was designed and produced by James Binnion of James Binnion Metal Arts LLC, Bellingham, WA.

The Layering and Bonding Process

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

1. Alternating sheets of 14k palladium white gold and sterling silver will be bonded for this overview. The central part of the ring shown at the top of the page is made of the same material. Each sheet of metal is about 1.5mm thick.
2. Chipp Allard, Binnion’s assistant who studied at the Revere Academy of Jewelry Arts, San Francisco, CA, 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 in a three-step process. After completing the abrasive procedure, he rinses the sheets, blows them with nitrogen to dry them then 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 the compression creates “intimate contact” between layers.
5. The torque plates with the compressed metal are placed in a container and covered with hot powdered charcoal. The container is capped and lowered into a kiln for diffusion bonding. Time and temperature for bonding depends on 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. Binnion reduces the thickness of the billet by 30%-60%, increasing 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 achieve the desired 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 process of high-speed carving, deburring, forging and shaping. This is where Binnion’s artistry comes into play. Notice the pattern is visible on the top and inside of the band. The 18k rails are soldered to each side of the band after the ring is formed.
9. To create the mokume-gane pattern, Binnion first uses a high-speed 1/2 horsepower turbine air tool running at 45,000rpm with a carbide bit to carve indentations into the billet.
10. After carving and deburring the billet, he inserts it into a custom-made ring-forming dye 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, deburring and forging.

Forming the Ring and Sizing

11. The billet began at 8.25mm wide and needs to be 6.5mm when completed. Final shaping and forming will be done with custom-made dies and a rolling mill.
12. Allard takes the ring blank and cuts it to length. He uses an adapted vice 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, preparing it for soldering.
16. Soldering is done at a custom soldering station with the hardest possible solder, allowing leeway for future alterations to 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’s necessary to “confine” the ring during the heating process with the custom holding device.

Finishing & Examples

All that’s left is the finishing. Binnion uses a variety of finishes on his pieces, but his favorite is matte, which highlights the contrasting metal colors. He often uses an etched finish on pieces containing silver. The photos on this page are examples of his designs, patterns and finishes.

17. This “tight star” pattern comprises 18k yellow gold, 14k palladium white gold and 14k red gold with a matte finish. The ring has a platinum liner and rails.
18. This 6mm comfort-fit band with a “tight star” pattern contains 14k palladium white gold, 14k red gold and sterling silver.
19. This 6mm ring with a “tight wood grain” pattern is made of 18k yellow gold, 14k palladium white gold and sterling silver with a mandarin garnet center and green diamond accents in 18k yellow gold bezels.

Next month, Part 2 will feature Binnion’s methods for installing liners and rails on his designs, servicing and aspects of quality for mokume-gane jewelry.

By Mark B. Mann

Technical Contributions by James Binnion of James Binnion Metal Arts LLC, Bellingham, WA

James Binnion has been a jewelry designer and metalsmith for over 20 years. He established James Binnion Metal Arts in 1991 to refine the art of mokume-gane. His line includes earrings, pendants and cuff links in addition to wedding, engagement and commitment rings. To find out more about mokume-gane and James Binnion Metal Arts, visit www.mokume-gane.com. For questions related to mokume-gane, contact Binnion at jbin@mokume-gane.com. For questions related to Binnion’s mokume-gane jewelry, contact Terry Binnion at (877) 408-7287 or tbin@mokume-gane.com.

Photographs by Mark B. Mann
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