Old Process, New Technology Modern Mokume.pdf

Old Process, New Technology: Modern Mokume

Gane

James E. Binnion

Owner

James Binnion Metal Arts

Bellingham, WA, USA

Bryan Chaix

Metalsmith

James Binnion Metal Arts

Bellingham, WA, USA

Introduction

Mokume gane is one name for a metal working technique developed in Japan

approximately three to four hundred years ago, in which two or more layers of

metal are permanently joined together in alternating layers to form a stack (or

billet). In the traditional Japanese technique the bond was achieved by diffusion

welding of the layers in a charcoal forge. On this laminated billet patterns of the

different colored alloys were created by a combination of cutting, twisting, and

forging of the laminate in ways to expose the various layers. The patterned billet

was then formed into finished work by applying standard forging and fabrication

techniques.

The name “mokume gane” refers to the visual

appearance of pattern in metal approximating that of

wood. “Mokume” literally means “wood eye”, which

would be used to describe a highly figured wood grain.

“Gane” translates as metal. So, in English, “wood

grain metal” is a near-literal translation.

Figure 1 Ring. 18K

Yellow, 14K Red , and

14k Palladium White

Golds and Sterling Silver

by James Binnion 2000

In making mokume gane, the craftsman selects alloys

for various properties. The most significant

characteristics of a prospective metal are color and

malleability. Color considerations include not only the

natural bulk color of the metal, but also various patinas

that can be developed by application of chemical

agents and/or heat. Depending on the amount of

material being made and the pattern desired, the sheets

are prepared in thickness ranging from foil to plates of

more than 0.250 inch. They are cut to the same shape and cleaned very

thoroughly to remove all dirt, oils, and (most importantly,) oxides. After being

stacked and bound together to ensure intimate contact over the whole of the

adjoining surfaces, the billet is heated in some way to create a bond. Depending

on the particular technique employed, the bond might be a solid-state diffusion

weld, a transient liquid phase diffusion weld a , or a liquid phase diffusion weld of

the individual sheets into a laminated billet. The laminated billet is forged to

strengthen the weld and to reduce its thickness before patterning.

Patterning consists of exposing layers from within the billet on the surface. This

may be accomplished by any of several methods. Carving into the laminated

surface with chisels or rotary tools, then either flattening the whole carved billet

to a uniform thickness or leaving it as a relief pattern, would be one way.

Punching or stamping from either the front or back side and then scalping the

surface down to a uniform level with files or by milling is another. Exposing the

end grain of the billet by twisting or forging on end is a third. Many interesting

possibilities are opened up by re-lamination of patterned material to create

complex patterns or mosaics. This is where technique and art meet. The limits to

patterning exist solely in the artist’s mind.

History of Mokume Gane, Late 1600s – Mid 1900s

The sword was one of the main areas of decorative metalwork in feudal Japan.

Some of the finest and most skillfully wrought metalwork in the world was used

in the creation and outfitting of many of these swords. The innovation of this

decorative technique is attributed to Denbei Shoami (1651-1728) a master smith

from Akita prefecture.

Shoami’s first piece is comprised of layers of copper and shakudo (a

Japanese copper alloy that contains 2.5% to 4% pure gold) laminated to

create a tsuba (sword guard) that was carved and flattened. The effect is

similar to Chinese and Japanese lacquer work known as quiri-bori

“where thick parallel layers of alternating red and black lacquer are

built up to a considerable thickness and grooves are deeply incised to

expose colored lines on their sides” b Shoami gradually learned to

flatten and to produce wood-grain patterns that lie on the surface of the

laminated mass c

It is likely that Shoami developed mokume gane by applying traditional forge

welding techniques to the non-ferrous metals used to decorate and complete the

sword. Many of the ferrous and non-ferrous mokume gane tsuba and other

fixtures exhibit patterns that are similar to the patterns developed in the sword

blades. He passed his technique down to other smiths and there are several

beautiful examples of mokume gane tsuba and other sword furniture that still

exist in collections around the world today k .

Besides the sword smiths and makers of sword furniture, other metalsmiths

learned to use the technique to make vessels and other objects. In his March 1893

lecture for the Society of Arts Professor W. Chandler Roberts-Austin describes

one such object, a vase that is in the collection of the British royal family.

… the body of the vase is of mizu-nagashi , (marble like pattern)

consisting of alternate layers of shaku-do and red copper d

Because of the great difficulty of its manufacture, mokume gane has never been a

widely practiced technique. Though there were not a great number of mokume

gane objects produced, some magnificent metal objects were exported to Europe

and North America in the late 1800s. Those pieces caught the attention of

scholars such as Roberts-Austin (above), and Raphael Pumpelly, who wrote what

was probably the first English language description of the process in 1866.

Beautiful damask work is produced by soldering together, one over

the other in alternate order, thirty or forty sheets of gold, shakdo ,

silver, rose copper, and gin shi bu ichi 1 , and then cutting into the

thick plate thus formed with conical reamers, to produce concentric

circles, and making troughs of triangular section to produce parallel,

straight or contorted lines. e

Pumpelly’s description of the layers being “soldered together” remained

associated with the process well into the 20 th century and caused great difficulty

for western smiths trying to replicate the technique. Modern analysis of early

mokume gane objects indicate that they were welded using diffusion techniques,

not solder a . It is almost impossible to use soldered mokume gane to fabricate any

object that requires significant deformation of the material in the manufacture of

the item. This is due to the relative brittleness of most solder alloys, leading to

the de-lamination of the soldered bonds during forming. This difficulty did not

prevent some work from being done by this technique by western smiths. There

were at least two western smiths that made work using mokume gane in the late

1800s and early 1900s. Both were influenced by the unique techniques and

styling of the Japanese smiths. One was Sir Alfred Gilbert f , who used mokume

gane in the central link of the chain of office for the Mayor of Preston,

Lancashire, England. Another was Edward C. Moore, who was Louis Comfort

Tiffany’s chief designer in the 1870s. Several mokume gane objects were made

in Tiffany’s workshops, including a coffeepot and flatware with mokume gane

handles.

Old Sheffield Plate

1 gin shi bu ichi an alloy of copper and silver where the silver content ranges between

50%-80%. It and a whole range of copper based alloys are used in many decorative

Japanese metal objects.

The Japanese were not the only ones to develop techniques of diffusion bonding

of non-ferrous metals. Thomas Boulsover also discovered diffusion welding of

silver to copper alloys in England in 1743. A cutler in Sheffield, England,

Boulsover is reported to have inadvertently bonded copper to silver on a knife

haft he was working on g . He discovered that the bonded metals would elongate

in unison when rolled. This discovery led to the production of a wide variety of

Sheffield Plate items for the growing middle class consumer in England who

could not afford solid sterling wares. The Sheffield Plate process for laminating

is very similar to the Japanese mokume gane lamination. The main difference is

that with Sheffield Plate there were normally only two or three layers, and during

manufacturing they were very careful not to expose the inner copper alloy

through the silver cladding. The smiths of Sheffield produced tons of this

material between 1742 and 1855, at which time it was almost totally superseded

by electroplating h .

There is no indication that the Sheffield Plate process was ever used to create

decorative multicolored metal surfaces by cutting through the outer silver layers.

It is of interest to note the different ways the same process was used by two

different cultures. The Japanese used the lamination process to create decorative

patterns using many different alloys of both precious and base metals, while the

English used it to cover the base metal to give an appearance of preciousness.

Industrial clad metal products such as 14k gold-filled sheet and wire and the

more recent 22k over sterling bi-metal are direct descendants of the Sheffield

plate process. There is still a demand for this type of product in the jewelry

market today.

Modern Studio Mokume Gane

In the first half of the twentieth century, mokume gane was almost totally

unknown in the west. Only scholars and museum staff such as Dr. Cyril Stanley

Smith a,b,i,j , Herbert Maryon f , and a small number of collectors k of Japanese metal

work were aware of it. In Japan it was also nearly unknown. Between modern

Japan’s movement away from the traditional crafts and the small number of

aging craftsmen practicing the art, it might totally have been lost.

It was C.S. Smith’s analysis of antique sword blades and fixtures that brought

ferrous and non-ferrous pattern welding to the attention of a group of metal

artists at Southern Illinois University at Carbondale (SIUC). By the early 1960s,

Professor L. Brent Kington and a group of his graduate students had embarked on

a course of research and experimentation that began with bringing the arts of the

blacksmith to academic art circles, and continued on to exploring the patterning

of ornate Asian, Islamic, and European blades in iron l .

This inquiry naturally led to experimentation attempting to replicate the mokume

gane found in items in museum collections. Many methods were tried, from

soldering to immersion of a solid in a molten metal. When bonding by these

methods, a “large” billet was 1/2” square by 1” long, and loss rates of 90% were

not unusual. Esoteric references in blacksmithing lore and literature to the forge

welding of copper by traditional blacksmithing techniques led to a pivotal change

in methods. In the words of Professor Kington, “a light went on in my head.”

Concurrently, Hiroko Sato Pijanowski and Gene Pijanowski, who are instructors

and metalsmiths with interests in traditional Japanese metalworking techniques,

saw a mokume gane vessel while visiting Japan in 1970.

… we viewed the annual “Traditional Craft Exhibition” at

Mitsukoshi department store in Tokyo. There we saw a raised

mokume-gane pot by Gyokumei Shindo. It was beautifully executed

having a surface effect of polished marble, but with none of the

technical and physical limitations of laminating nonferrous metals

with silver solder. Since then we have been fascinated with mokume-

gane. c

This fascination lead to another trip to Japan to work with Norio Tamagawa, a

skilled craftsman in the traditional form of mokume gane. The Pijanowskis

returned to the States and started publishing papers c,m about their research into

the mokume gane technique and teaching workshops to spread their knowledge

of this technique.

These parallel pursuits were bound to intersect. In the spring of 1977, the

Pijanowskis were invited to SIUC for a weekend visiting artists’ lecture and

workshop. They shared their knowledge of Japanese alloys, patinas, and

methods. The Carbondale group shared their understanding of the applications of

the blacksmiths’ art. n A significant innovation from SIUC student Marvin Jensen

was the use of “torque plates” to compress the stack during the laminating

process. The torque plates consisted of two

mild steel plates approximately one quarter to

one half inch thick that were drilled around the

perimeter and four to six bolts were passed

through the holes and tightened or “torqued”

down to provide greater pressure on the sheets

during lamination than the heavy iron wire

used by Tamagawa and the Pijanowskis. This

increased contact pressure and reduced the

time required to prepare the sheets. They no longer needed to be ground

perfectly flat, since the tightening of the bolts removed small irregularities in

flatness of the sheets. This innovation greatly improved the success rate of the

lamination process.

Figure 2 Torque Plates

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