n Members of the Graduate Program Southern Illinois University Carbondale:
Marvin Jensen, Philip Baldwin, Stephen Brunst, Lori vanHouten, William Ard,
Janice Nathan, Randy Jones, Prof. L. Brent Kington, Prof. Richard Mawdsley;
“Return to the Forge: Extended Research into Mokume-Gane and Granulation”
Society of North American Goldsmiths 1979
Seppo Renfors wrote in message ...
"Paul K. Dickman" wrote:
Seppo Renfors wrote in message ...
I already said it was brazing. I couldn't think of the specific
decoration name before, but it is used in making "mokume gane" as
found, and originating on samurai sword handles from about 1600 -
1800.
Actually, Mokume Gane is not a brazing process, but a diffusion bonding
process similar to forge welding.
By definition "welding" does refer to melting of material to be joined
- be it in a forge, oxyacetylene or mig welding or whatever.
I didn't say it wasn't welding, I said it wasn't brazing.
It occured well below the melting point of all the alloys involved.
Actually no "alloys" are involved - they are pure materials laminated
in mokume gane.
Horse hockey.
Here's a quote from;
http://www.mokume-gane.com/Papers/Sa...Fe%20Paper.pdf
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” Shoami gradually learned to
flatten and to produce wood-grain patterns that lie on the surface of the
laminated mass.
I cannot speak to the state of the science now, but back in the late
70's,
when I was doing research on it in college, our theory was this.
I'm pretty sure that will be close enough still :-)
At elevated temperatures the grain structure of the metal undergoes
enormous
changes (this is what causes annealing) as the grains grow they can grow
between separate but closely associated pieces of metal, Assuming that
the
junction is chemically clean and free from oxides.
Isn't this what "brazing" refers to?
No, brazing requires a filler metal with a melting point below the metals
being joined
Are you suggesting silver "sweats" (forms liquid beads) way below its
melting point?
Actually it can. metals alloyed together have an Gestalt proportion
called
the eutectic. In the case of silver and copper it melts at a lower
temperature then either.
I'm aware of that, but these are not alloys - these are pure metals
made into a "Dagwood" sandwich - therefor the "eutectic" thingo
doesn't apply. If on the other hand you speak about a real
copper/silver alloy, as per your experiment - that is a different
story.
Again, they are not necessarily pure metals.
If they were (pure copper and fine silver) That bonding temperature would be
roughly 2/3 the liquidus temp of the silver/copper eutectic.
But the term sweats as it applys to Mokume gane is kind of a misnomer. It
comes from the amount of blacksmiths we had on the project.
I look through my notes and found the origin of the term sweats in this
context, and I was wrong. I thought it was the crew I worked with as an
undergrad grunt at SIU in
Members of the Graduate Program Southern Illinois University Carbondale:
Marvin Jensen, Philip Baldwin, Stephen Brunst, Lori vanHouten, William Ard,
Janice Nathan, Randy Jones, Prof. L. Brent Kington, Prof. Richard Mawdsley;
“Return to the Forge: Extended Research into Mokume-Gane and Granulation”
Society of North American Goldsmiths 1979
but it was the Pijanowskis in
Pijanowski, Hiroko Sato and Pijanowski, Eugene M. “Lamination of Non-
Ferrous Metals by Diffusion: Adaptations of the Traditional Japanese
Technique
of Mokume-Gane” Goldsmiths Journal August 1977 pg 21
The Pijanowskis used a liquid phase bond that required a melted surface.
However after Marv Jensen developed the torque plate clamping, I think that
even they went to the lower temp solid state diffusion
Whoever it was that said this, it was a person familiar with making
mokume gane. It is a visual indication of having reached the desired
point "when the silver starts to sweat" not the copper, but silver,
that has a lower melting point - a method that was used in ancient
times before thermometers and fancy little bench top gas kilns were
invented.
So you are saying that native Americans working with stone tools could
manage to cast a largely uncastable metal, but the Japanese, who raised
metalwork to an artform rarely duplicated, couldn't judge temperatures
As to people familar with making Mokume gane, I added two more photos to
http://tinyurl.com/3cw7p
Showing some of the Mokume gane I made during those years.
Paul K. Dickman
It was a term they used in forge welding iron, and refered to the surface
geting a greasy or oily appearance as the welding temperature is
acheived.
...which is only just below melting point - yes THAT look I recognise.
For Mokume, the rule of thumb that we used was that this temperature was
roughly 2/3 of the eutectic temperature of the alloys involved.
That would be fine IF you were using "alloys" - in my example no
alloys are involved.
Again an infinite number of alloys could be used.
And, unless you are merely bonding copper to copper alloys will be created
by the process.