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.

It occured well below the melting point of all the alloys involved.

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.

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.


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.

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.
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.

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.

Paul K. Dickman