[TheForge] mokume- gane

[Dr. Stephen A Bloom]

At 01:40 AM 8/8/2012, Dan wrote:
>  I read that you can use US quarters as your start press, heat, 
> then weld  but could not find anything about if it needs flux. 
> Anyone got a link or a book on a simple start for  mokume game?
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I've worked out a reasonably reliable system:

(1) acquire some copper rod stock (3/32 or 1/8). I've found some at 
an ACE hardware but heavy electrical wire will do

(2) drill/punch an appropriate size hole in $3 to $4 worth of 
quarters. I rigged up a Roper Whitney punch to self-align the coins 
but a drill will work.  You want to get the hole dead center on all 
coins, so a jig would help. You want the edges of all coins 
to  align, so after riveting, you can straighten the stack in a 
decent machinist vise.

(3) pickle the coins (Sparex #2 is what I use but any jewelry pickle 
ought to work). I started with just wire brushing them but the pickle 
is easier (use a copper or ceramic pot).  What  you are doing is 
removing any oil, grease, and oxide films, After this, handle them 
from the edges

(4) stack the coins over the rod material and rivet them together - 
you now have one item to handle instead of 12 to 16. I've have done 
them clean and with silver brazing flux and have seen no difference.

(5) get a couple of plates to act as hot surfaces - I use 1/4" thick 
x 2" x 2" stainless with a tab welded on to allow tong manipulation

(6) fire up a gas forge and put the plates in the forge.  When they 
get to 1800 F or so, put the stack on a plate. Watch it like a hawk 
and keep turning the stack over to get the heat uniform. When you see 
a hint of weeping at the edge (tiny bubbles), lift the plate with the 
stack to (a) a power hammer; (b) a treadle hammer' or (c) an anvil - 
place the other plate on top and whack it.  Compress to about 50% of 
the height.  If you do not use the plates, the heat sink of the anvil 
and hammer faces will cool the top & bottom coins relative to the 
center ones and the center ones will extrude over the end ones, i.e., 
you'll find the end coins embedded inside the coins in the 
center.  You can easily melt the stack. I've done this in my Damascus 
forge and just scrapped out the melted copper w/o any long term 
problems to the forge. The plates will help and watching it carefully 
will help even more but a melt does not mean a dead forge.  Of 
course, it might be a function of the castable refractory on the 
floor of my forge and left over borax, so pays your money and take 
your chances.

(7) you can forge the stack into a rectangle (thus keeping waste to a 
minimum).  Just keep a plate in the forge with the stack, lift both 
out to an anvil and with the plate between the stack and the 
anvil,  tap two or three blows on the edge of the stack and one to 
flatten, then back into the fire.  One extra hit or one that is too 
hard, and the stack will separate, so go lightly.  A set of 
laboratory tongs (do a  Google search for "

Humboldt Manufacturing Double Bend Crucible Tongs H-23385" as an 
example) are really helpful.  You can drill a matrix of shallow holes 
in the stack and them flatten out to get neat swirls. You can even 
twist a stack (forge into a cylinder, twist, forge back to a block) 
but the pattern really isn't cool enough to justify the effort.

Steve