2010 – Mokume Gane Firing Methods and Their Effects on Appearances and Bond Strengths
Industry Leader Award
Collaborative Research Award
Presented and written by: Chris Ploof—Chris Ploof Designs, USA; Materials support provided by Stewart Grice – Hoover and Strong, USA
Mokume gane can be made with both the solid state (or electric kiln) method, as well as a liquid phase method (traditional Japanese method or forge/torch method). Some makers insist that the liquid phase method results in muddy bond interfaces that don’t look as nice as solid state methods. Chris disagreed and this is his research into this simple, “equipment-lite” prices suitable for small scale mokume gane billets. Winner of both the Santa Fe Symposium Collaborative Research Award and the Santa Fe Symposium Industry Leader Award in 2010. Mokume gane is an ancient Japanese metalworking technique that involves the diffusion bonding of pure metals and alloy sheets into a billet that is forged, rolled and patterned, resulting in patterned materials. The practitioners of the art of mokume gane have found that billets that may look well-bonded initially can fail catastrophically during the reductions that create the patterned materials. In 2005 James Binnion, Andrew Nyce and Stewart Grice studied solid-state diffusion bond strength as a function of open and closed torque plate bonding apparatus, utilizing the newly developed Thermal Expansion Mismatch Torque Plate System (TEMTP). Their paper (presented at the 2005 Santa Fe Symposium) demonstrated that the TEMTP system resulted in increased bond strength compared to the open torque plate system. However, the authors did not include downstream processing within the scope of their study nor did they consider the effects of time and temperature on bond strength. In 2009, Ploof, Grice and Nyce presented a paper that looked at the role reduction plays in developing bond strength. Several styles of reduction were examined with various results. This paper is an adjunct to both of these preceding papers. This paper examines a method of liquid-phase bonding and the resulting mokume gane’s strengths and appearances. It includes a “how to” based on many years of trial and error, and process improvements, which will enable someone with little mokume gane experience to make “torch-fired” billets in a reasonably well-equipped studio, and to begin to use mokume gane in their own designs.