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How to alloy copper into Shakudo


#1

Hi all, I have a question about copper. I am going to teach myself
how to alloy copper into Shakudo, shibuchi, and a few other japanese
alloys I have come across (those 2 are spelled out in my book heh) I
don’t have any experiance alloying metals, but I have a knack for
self training (I made mokume with silver and copper in 5 hours from
-0- base experiance and one source of info, and it was flawless and
beutiful). If anyone here can give me some basics on how to go about
alloying copper with gold/silver please let me know.

I am assuming the basic process is to melt the appropriate amount of
metals with some flux in a crucible, and give it a good mixing, but
what temps? how muych flux, how much to mix it, etc. Any info you all
can provide would be great, and I’ll gladly post a full journal of my
experiance with making the metals if you’re all interested.

ok, thanks for your time
-Doug


#2

Hi Doug - I have made shibuichi, following Andy Cooperman’s
instructions in the July 2000 issue of Lapidary Journal. It was not
a very scientific attempt on my part i.e., no attention to order of
mixing, just threw it all into a crucible (68%cu, 32% fine silver) ,
scattered some borax on top and had at it with a torch, needed to a
second torch to get it to completely melt, since I was using a presto
lite w/ acetylene - no ox supplement… Worked quite well, and I am
still using it. Textures well into little bubbles and oxidizes
nicely with the torch, and using various patinas.

Now its your turn - and anyone else who is working with Mokume and
marriage of metals - I’m trying to follow in Carrie Adells footsteps,
but so far, her reputation is safe!

I have been trying to create a 2 layer billet - copper and sterling

  • and using the soldering method as described in Steve Midgett’s
    book. So far, not too much luck. Could you pass along your
    technique or hints? I don’t have a kiln, so that is likely part of
    the problem. My results so far include lots of bubbles between the 2
    sheets. I am in the process of trying to sweat solder them by
    coating one sheet in stead of binding the 2 sheets together and then
    trying to flow the solder into them (this yielded the bubbled results
  • possible because the flux was not dry b-4 assembly and soldering.

Anyway, any help will be appreciated!!
Ivy in Oakland (still wishing it was Taos)


#3

ok, since you asked, here’s my method for making Mokume, it’s far
from perfected as I’ve only done it a few times. I use an Aim bead
annealing kiln, they’re about $400 from a glass blowing supply store
(try www.waleapparatus.com ).

First thing I do is get my metal. I use Sterling and copper between
30 and 16 ga. Cut them down to approx 1" x 3", clap them together and
file the edges so they all line up perfectly. This is very important
later on when rolling to avoid separation. once that’s done I undo
the clamp, then sand each sheet on both sides with a 200 or so grit
emery paper, then take it down a little more with 600 grit. I finish
the sheets off with a soak in an ultrasonic cleaner, then alchahol as
a final cleaner. This may seem like I’m over doing it, but I haven’t
had any problems since my first stack (It didn’t bond well, and
wasn’t cleaned as well).

Next I get my torque plates ready. These are 6"x6"x1.25" mild steel
plates with 1/2" holes drilled about an inch in from each corner.
I’ve used thinner steel, it eventually warps. I had the steel
already, so I just made it myself. Your best bet however is to
contact a welding or machine shop in your area. I have no idea what 2
plates will cost, but I think I used about $20 or so worth of steel,
and I was getting it at a wholesale rate. Anyways. Take the two
plates, make sure they are clean and perfectly smooth on the inside.
Coat the plates with yellow ochre, and carefully place your stack of
precious metals between the two plates. No flux is used, it’s just
bare metal on bare metal, and VERY clean.

Next step is tightening it all down. For this I start in a vise,
clamp it all together, make sure the stack is still well aligned. if
not, readjust. I then put 4 bolts, with washers on both sides of the
bundle. tighten up the bolt equally, a torque wrench is best for
this. get it as tight as you can by hand, don’t bother with over
tightening it as this will only snap your bolts off.

Then I put the whole device into a small metal box I made with some
heavy (around 16 ga) sheet metal, made to be about an inch bigger in
all dimensions than my loaded press. I fill the box up with pellets
of bone charcoal, but any form of charcoal should do, to reduce
oxygen. I also lined the floor of my kiln with charcoal, and pile in
a few very well burned chunks of wood I have for this purpose. The
idea is to reduce the open space in my kiln as much as possible with
material that will create a reduction environment. I have been
thinking of a way to use argon to flood the kiln, but not sure yet if
I can seal the kiln well enough.

Once the press is in the kiln I close it up and set the kiln to go
up to 1500F degrees and let it sit for 4-5 hours. I basically just do
something else. This is where the magic of diffusion takes place.
Under the very high temperatures the steel expand with the copper and
silver to create pressure that you just can’t make any other way.
This process allows the silver and copper molecules to migrate into
one another, and forms a solid billet. When I’m ready to take the
metal out I turn up the kiln a bit to 1550 for about 5 minutes, I’ve
found this added little burst at the end actually can make a
difference.

Using tongs I pull the box from the kiln and dump out the press on
my studio floor (it’s a messy process). I grab the press (still red
hot) with the tong and place it on an anvil. I strike it several
times with a firm, but medium hard blow on the top, turn it over and
do it again. At this point I use bolt cutters to go in between the
plates and cut each bolt quickly. I remove the billet (still almost
red hot, too hot for gloves) and proceed to, for lack of a better
term, forge the hell out of it. I generally work them until my arm is
sore, and they’re cool enough to pick up bare handed. I’m not trying
to flatten the billet, just “feeling” it, letting it know that it’s
only just begun.

From this point you can treat it like any other ingot or billet.
Mine tend to be about 1/4" or so thick, which I will forge and roll
out to 16ga and use in the next billet to build up layers. I’ve only
done this Mokume thing about 5 times now, so my process is far from
perfected, but it’s at a point now where it’s basically without major
flaw. So far I have only made 1 billet from previously laminated
metals for 30 layers of silver and copper total. (5 16ga sheets of
alternating silver/copper in 6 layers)

Anyways, that’s my process, as for what I do with the metal, well…
I store it for the moment, but I’ll get around to working more of it
soon So far I have made a couple really nice emerald rings, but
that’s about it. If you have any more questions, or need more
specific info, let me know, I’m sure I missed something, it’s late, I
need sleep, it’s final week, my life is stressed =) And please let me
know how it comes out. I truly believe the only way to success with
mokume is to just really get into it, and do it. Make sure you take
care of the metal before you press it, and afterward pour all your
energy into forging it. Nothing in my life right now feels better
than pounding away my frustration and anger and fears into the
metal, and it’s what I think makes the difference. Don’t give up, my
first stack sucked, delaminated the day after I rolled it, I almost
gave up, thinking my equipment couldn’t handle it. Glad I decided to
give it another go. ok, time for sleep, good luck

-Doug


#4

Hi Doug,

I have a question for you. are you sure what the temp in your kiln
is? because at 1435F the silver and copper will form a eutectic
alloy and melt into each other and then the layers tend to slide and
slip around and it gets kind of messy. Otherwise it sounds like you
have the mokume process down. Clean metal is the most important
thing in mokume.

BTW to increase the life of your kiln elements do not fill the kiln
with charcoal as it creates a reducing atmosphere and will reduce
the protective oxide layer that forms on the kiln elements and they
will go away much faster. I have a AIM kiln that I have been using
for 10 years now. The box you have made and filled with charcoal is
more than adequate for your laminations to work. –

James Binnion Metal Arts Phone (360) 756-6550 Toll Free (877) 408 7287
Fax (360) 756-2160 http://www.mokume-gane.com @James_Binnion
Member of the Better Business Bureau


#5

I have made soldered mokame and didn’t have problems. I coated each
sheet with the solder before “sweating” them together. I didn’t use
it as a solid piece but I have rolled some of it down quite thin. .
.maybe 28 gage. I have used it as strips and I have soldered strips
together to make different patterns. I have also wrapped wire and
flooded it with solder. This makes some very nice herringbone
patterns after hammering flat. I think that it’s better to hammer
than to roll. By hammering, the strip can be made wider but with the
roller, it’s too easy to feed the wire in the long way. This is not
my idea but I can’t remember the book that I saw it in. If I do
remember, I’ll let the list know. My only experience with kiln firing
a stack resulted in a rather nice kiss, the Hershey kind.
Unfortunately, it was a student who lost the metal.

Marilyn Smith