Chris is dedicated to the science behind his processes and has presented scientific papers at industry events. He continues to better his processes, not just for manufacturing the jewelry but also for making the metals used in the jewelry industry better.

 

Below is a list of papers presented at the Santa Fe Symposium by Chris. Free downloads are available at santafesymposium.org.

2019 – Practical Application of a Rose Engine in the Modern Shop

Presented and written by: Chris Ploof—Chris Ploof Designs, USA; Materials and Metallographical support provided by Stewart Grice – Hoover and Strong, USA

 

In 2016 we added a rose engine to our shop. This paper journals our approach to using it for working various metal objects and also details a simple process for a non-traditional pure gold and silver inlay method. How many times have you looked at a machine and wondered how it works or at a piece of jewelry and wondered how it was made? A rose engine is a type of ornamental lathe used extensively by jewelers in the 19th and early 20th centuries. This paper will open your eyes to what happens when you take a traditional tool and combine it with non-traditional uses. Our method for bonding inlays into rose engine cut designs will be showcased including metallurgical examinations of those bonds.

2016 – Mokume Gane History and How-To: A Survey of Technique

Presented and written by: Chris Ploof—Chris Ploof Designs, USA; Edited by James Binnion—James Binnion Metal Arts, USA

 

Several papers had been presented since the early 2000’s detailing various scientific tests of mokume gane in various states. A decision was made to detail current methods used in a production environment by top producers of modern mokume gane materials. This paper will showcase the history and technique of mokume gane from its beginnings in feudal Japan to its use as a jewelry material by modern smiths around the world. Mokume gane is a demanding technique that even those well versed in jewelry metals struggle with. This presentation will illustrate the techniques used daily by two of the most prolific makers of quality mokume gane in the world. The scientific method will be stressed rather than scientific testing. This is a practical “how-to” presentation, and is the first time the full process in daily use will be presented with a goal of showing a person with general skills in jewelry making how to make mokume gane like the experts.

2015 – Mokume Another Way

Presented and written by: Chris Ploof—Chris Ploof Designs, USA; Materials support provided by Stewart Grice – Hoover and Strong, USA

 

Thinking outside of the box has always been a specialty of ours. Typically, seamless mokume gane is a laborious process involving drifting of a piece of stock. This paper shared our method for making small amounts of seamless mokume gane tubing for ring production. This paper earned The Santa Fe Symposium Jewelry Technology Leader Award 2015. Mokume gane rings are typically manufactured from patterned flat stock that is bent around to form a ring. This paper will detail another method of production for the small shop—the use of a hydraulic press to deep draw tubing for rings. It will show how to bond and prepare mokume gane billets for deep drawing, how to deep draw multi-layered material and how to pattern deep-drawn tubing into unique and engaging rings. This process is economical and can be accomplished with tools found in a well-equipped jewelry studio. Examples of beautifully patterned mokume gane rings produced using this method will be shown.

2014 – Mokume Gane Bonds: The Effect of Quenching on Bond Strengths

Presented and written by: Chris Ploof—Chris Ploof Designs, USA; Materials and Metallographical support provided by Stewart Grice – Hoover and Strong, USA; Edited by Andrew Nyce – Andrew Nyce Designs

 

Mokume gane is a difficult process. Along the way from sheets of metal to a diffusion bonded piece of ring stock there are many places errors can be made. This paper investigates the relationship between how the metal is cooled and bond strengths. Winner of the 2014 Santa Fe Symposium Collaborative Research Award. Mokume gane is a seventeenth century Japanese metal-working technique, in which three or more layers of metal are permanently joined in alternating layers to form a stack or billet. In recent decades it has been re-introduced as a jewelry art form. The metals can be difficult to bond and work. This paper examines the relationship between water quenching and air cooling to find an answer to which cooling method provides the best material suitable for manufacture into finished jewelry items.

2011 – Mokume Any Other Way?

Presented and written by: Chris Ploof—Chris Ploof Designs, USA and Joe Strauss – HJE, USA

 

Mokume gane is beautiful and time consuming to make. But what if there was another way? Working with a a leading industry expert on the use of powdered metals, this project demonstrated that there are other methods you can use to make mokume gane products. Winner of the 2011 Santa Fe Symposium Collaborative Research Award. Mokume Gane is a material- and labor-intensive process. Materials are diffusion bonded and then worked to consolidate and shape the billet. Once shaped, considerable additional working, with its attendant loss of material, is required to produce the desired pattern. Only then can the material be made into individual jewelry items. In addition, the traditional mokume gane methods limit the type of materials that can be bonded together as the extensive downstream processing can destroy the billet by failure of the bonds between materials with disparate properties. The paper will describe methods to make net- and near-net-shape mokume gane jewelry items or blanks on a per-piece basis. This alternative method will alleviate many of the disadvantages of bulk mokume gane processing through creative use of solids and powders. These methods will also provide for new patterns specific to this method and the materials used, as well as the potential to create new combinations of metals. This paper is essentially two studies and will thus contain two discrete sections. Section I will cover the science and engineering of diffusion bonding and the development of hot pressing methods used to make samples. Section II will cover the conversion of these samples into jewelry items and compare testing, properties, and aesthetics with materials and items made by conventional mokume gane methods.

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.

2009-Mokume-Gane Billet Reductions and Their Effects on Bond Strength

Industry Leader Award

 

Making a billet stick together is only one of the several steps to creating quality mokume gane. How you reduce it to usable materials plays a huge part in the strength and quality of the resulting materials and finished jewelry. For Chris’ first foray into scientific research, he chose to use the best available firing methods and study various reduction process to ascertain the best way to make the highest quality mokume gane. This earned Chris the 2009 Santa Fe Symposium Industry Leader Award. Chris is the only winner as a first time presenter of this prestigious award. Mokume Gane is an ancient Japanese metalworking technique involving the diffusion bonding of pure metals and alloy sheets into a billet that is forged, rolled and patterned, resulting in patterned materials. In 2005, James Binnion, Andrew Nyce and Stewart Grice studied 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 demonstrated that the TEMTP system resulted in increased bond strength as 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. This study is a continuation of the work they began and includes the effects of time and temperature and selected downstream processing techniques on bond strength, where bond strength was measured by rolling samples to failure on edge. Based on the results of this study, it was found that longer firing cycles produce stronger bonds. Cold forging, either by hand or using a hydraulic press, produces bonds that were among the strongest of the tested methods of reduction. Hot and cold forging using the hydraulic press creates strong materials. Hot forging takes advantage of the elastic deformation of the heated billet, which allows for much greater reductions. This method is a good fit for the small, well-equipped shop. Cold rolling, as accomplished with the smaller diameter rolls of the typical small shop rolling mill, seems to be less than adequate when compared to hot and cold forging.