Hi Karen,
OK, I'm confused. I certainly conceded the point on your
wonderful description of soldering the "stack" together. BUT...
how on earth do you make mokume and other laminations without
rolling them? Am I misunderstanding your post completely? I was
taught (and have read) that the process of rolling, annealing, and
thinning and then filing and continuing the rolling process was how
you achieve the patterning variations of mokume. It sounds like
you are saying that's not the case???
The materials added to make solders melt at lower temperatures than
the parent metals all tend to be more brittle than the parent
metals. There are huge shear stresses induced in the metal when
rolling. These stresses are concentrated in the areas where the
metal is least ductile, in other words right at the solder joints.
This leads to the cracking that occurs when rolling the soldered
laminate. Now it is certainly possible to make a form of mokume gane
via soldering, however it is difficult to work with due to the
cracking, de-lamination caused by rolling and forming it also
presents great problems in soldering it during fabrication due to
the massive amount of soldering done on the laminate. It would be
very unlikely that a vessel could be raised from soldered mokume.
None of the traditional Japanese mokume gane work I have seen is
soldered. The vast majority of modern mokume gane as well as the
traditional work is bonded via diffusion processes where no solder
is involved.
The idea that mokume gane is soldered dates back to the last half
of the 1800’s. However the people who put this idea forward never
made any mokume. There are two diffusion processes one called
transient liquid phase diffusion bonding and the other is solid
state diffusion bonding. In the transient liquid phase process the
stack is heated in a charcoal forge fire to the point where some of
the alloys in the stack just start to melt, it is then removed from
the fire and hot forged to to complete the bond. This molten or
liquid phase in a way is similar to solder in that it wets the
surfaces and aids in the fusing of the metals in the stack, but it
is the hot forging that really develops the strong bond between the
metal sheets. This is the way the traditional mokume laminates were
done the presence of a liquid phase in the process leaves an area at
the layer boundaries that looks somewhat like solder and this is
probably why the English scholar W. Chandler Roberts-Austin and the
American Raphael Pumpelly who first described mokume called it a
soldering process.
“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 , 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.”
Pumpelly, Raphael, “Notes on Japanese Alloys” American Journal of
Science vol. 42 1866
Comments by Pumpelly and Roberts-Austin are what led western smiths
who were trying to recerate the mokume gane process to attempt it via
soldering. It was not until the 1970’s when Hiriko and Gene
Pijanowski went to Japan and learned the traditional process from
Norio Tamagawa that western metalsmiths learned that solder was not
the answer. Upon returning Hiriko and Gene taught workshops in the
traditional technique and started the renaissance in mokume gane.
The solid state diffusion process is accomplished by bringing the
metals in the stack up to a point just below where the liquid phase
appears (hence the term solid state as no liquid phase is present)
and holding it there long enough for a bond to form due to crystal
growth in the heated alloys. It is also typically hot forged to
increase the bond strength. The solid state diffusion process is
typically a modern technique because it is much easier to accomplish
in a temperature controlled kiln rather than a open fire but can be
done either way.
For more info on making mokume gane check out
Books:
Both of these books are excellent resources for technical how to
(Disclaimer I wrote one of the chapters in Steve
Midgett’s book so am some what biased about it :-))
“Mokume Gane A Comprehensive Study” Midgett, Steve
“Mokume Gane” Furguson, Ian Krause; (June 15, 2004)
~ Mokume Gane - A Comprehensive Study
By Steve Midgett
price: $34.95
Product Information
Media: Hardcover
Manufacturer : Earthshine Press
Release data : 2000
~ Mokume Gane
By Ian Ferguson
price: $16.97
Product Information
Media: Paperback
Manufacturer : Krause
Release data : 15 June, 2004
Online:
A PDF file of a paper I presented at the 2002 Santa Fe Symposium
that contains both historical and modern methods with a
list of references at the end.
http://mokume-gane.com/Pages/What_is_Mokume.html#Anchor-In-49575
Jim Binnion
James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160
@James_Binnion
Member of the Better Business Bureau