What do the Mokume guys do? Has anyone forged all the way to a finished sheet? Was it usable for severe forming?
Oh yes, absolutely. It produces the highest quality sheet if done
well. See the work of Norio Tamagawa, Wayne Meeten and Marvin Jensen.
All produce large vessel forms from mokume gane that is forged to
sheet.
James Binnion
James Binnion Metal Arts
Silver 925: 70% Silver 800: 55% Gold, Yellow 18kt: 65% Gold, White 18kt: 65% Gold, Yellow 14kt: 55% Gold, White 14kt: 55% Gold, Yellow 9kt: 50% Gold, Red 9kt: 55%
This is theoretical figures and frankly have very little use in
practice. There variables like degree of annealing, annealing
temperature, how it is quenched, size of the stock, size of the
quenching bath, and etc. The list almost endless. You stop rolling
and anneal when your eyes and experience telling you to stop. That is
all.
Leonid Surpin
You stop rolling and anneal when your eyes and experience telling you to stop.
Yes, experience really is the best, but use of a chart as a starting
guide can narrow some of the parameters down somewhat.
We are all believe that people should learn by doing. Could you
please quantify a few of the key observation points for us? Perhaps
some guidelines too? I believe that was the quest of the original
posting.
All the best.
J Collier
Metalsmith
We are all believe that people should learn by doing. Could you please quantify a few of the key observation points for us? Perhaps some guidelines too? I believe that was the quest of the original posting.
Well, beginner should not use motorized rolling mills.
I would suggest hand cranked. One should not struggle too much while
milling stock. You should feel slight to moderate resistance. If it
starts getting difficult, time to anneal. If you see the signs like
metal begins to buckle, you have taken it too far. I do half a turn
on
my mills and monitor the thickness constantly. As long as reduction
is
even after every pass, you can continue. If you start notice that for
the same amount of turn, the reduction is less and less, it is your
indication that it is time to anneal.
Leonid Surpin
Alright, enough of the confusion with force for small versus large
rollers. This is a simple ratio of diameter of handle and the
diameter of the roller. So a 12 inch long crank, and the roller is
one inch or two inch, will move stock at a 12:1 or 12:2 (6:1) ratio
of force. Obviously, twice the force is required for the large
roller compared to the small one. This is simple math. If there is a
4:1 ratio, then that is figured in as well, but it is still twice the
force needed for the large roll. It would only be easier if the
ratio is different for one size roll to the other. Also think of how
much stock will be passed for each revolution of the crank, the
larger roll will move more stock, and will take more force.
Tom Parish
Designs by Suz