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Technique and Process involved in creating Mokumé-Gané (Mokumé)

A mokumé billet is actually the many layers of metal which have been bonded through heat and pressure to work as one piece of metal. It is comprised of up to 30 layers of metal with alternating colors.  This mokumé billet is the raw material that I use to create my jewellery.  Below is a brief explanation as to how a mokumé artist forms a billet.

1. The die is prepared with boron nitride to prevent the metal sheets from fusing to the steel die body while in the kiln.

2a. The sheets of metal are filed precisely to fit the die body.        

2b. The filed sheets of metal are then cleaned and set in the die body. These 2 steps are both important and time-consuming. If the metal is not cleaned properly, the slightest bit of dust or dirt can prevent the metals from bonding.

3.The die body and plates are bolted and compressed at high pressure to ensure that the sheets of metal that are used in creating the mokumé billet are in good contact and will bond.

4. The entire die body is placed in a stainless steel bag with charcoal (to keep metal from oxidizing, which would prevent bonding) and placed in a kiln at high temperatures for 5-7 hours. The time and temperature are determined by the specific alloys that the mokumé artist has chosen for the billet. Without the correct combination of heat and time, the metals would fail to bond.

5. The die is removed from the kiln and allowed to cool in a manner appropriate to the metals used. Once cool, the billet is removed from the die body.

6. The mokumé billet is then cleaned, filed and inspected for any evidence of failure.

7. Repetitive use of the hydraulic press is necessary to reduce the thickness of the mokumé billet

8a. Once the billet has been reduced sufficiently with the hydraulic press, the metal is put through the rolling mill to reduce in small increments If it is reduced too much in one pass, the metal could crack.

8b. The billet is taken down to a thickness of approxiamately 3mm.

9. The mokumé billet must be annealed with a torch or in a kiln between each pressing &/or after a few passes through the rolling mill to soften the metal. The metal would otherwise become brittle and split.

10. Each mokumé artist will use specific techniques to pattern their metal. It can be twisted, gouged, and punched using tools like chisels or burrs to “draw” on the metal. Once gouged, the metal is again rolled and annealed until the gauge (thickness) desired is acquired.

11. The end result is the metal known as mokumé-gané. The jewellery that I create from this metal can have a matte finish, which is a little more subtle, or can be etched in acid to create a beautiful relief between colors.