Hi folks I know this is a somewhat narrow area of interest but I
just had it brought to my attention again today so I thought I would
climb up on my soapbox.
I had a young couple bring in a pair of mokume rings made by another
goldsmith today for me to look at. They were a gold and shakudo (an
alloy of copper and gold typically 4-6% gold) combination. I had to
tell them that shakudo is a very poor choice for a wedding ring or
for any ring that gets full time wear because it will corrode away
in very short order (1-5 years depending on the individuals body
chemistry and the environment it is exposed to). Another mokume
artist was kind enough to clue me into this years ago before I had
too many shakudo combination rings of my own out there and I
immediately stopped marketing them. I have since had a chance to
look at a couple of my shakudo combination rings that have come back
for sizing or other service. It is amazing how fast the shakudo is
etched away by the action of skin chemistry and environment. My
personal decision on what to do about this is to buy back or
exchange any shakudo ring I produced that a client wishes to return.
Mokume is gaining in popularity and I am seeing lots more people
making mokume wedding rings, many with copper, shakudo or shibuichi
elements none of which are stable enough for long term day to day
wear in a ring. Given the divorce rate you could make a joke about
the ring self destructing about the same time the marriage does,
however the vast majority of people do not enter into a marriage
with the idea that it will not last. I understand the attraction of
the color and historical significance that these metals provide but
silver, gold and platinum or stainless steel are much better choices
for laminates in a ring that is intended to be the symbol of a life
time union. I feel that it is important for us as the makers of
these symbolic rings to take into consideration how they are going
to wear and how well they will stand up to the rigors of day to day
wear along with the aesthetic issues of the design.
I realize that there are going to always be clients who don’t care
how durable the metals or stones are that they desire in their
rings, they want what they want. And as long as we disclose to them
what the issues are then it is their choice and they will have to
deal with the consequences of that choice. However I feel that we
must make them aware of the issues or it reflects badly not just on
the individual goldsmith but on the trade as a whole. It is exactly
the same as disclosing treated stones or fracture filled diamonds.
I take great pride in my mokume rings and I am sure that others who
make mokume rings feel the same way about their work. If that other
artist had not been kind enough to clue me in to the corrosion issue
I would have blithely continued to produce rings with shakudo in the
laminate.
I don’t want the term mokume ring to become synonymous with
something that falls apart in a short period of time. So please,
think about the materials you use in your work.
End of rant,
Jim
Jim Binnion
James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160
@James_Binnion
Member of the Better Business Bureau
Hi folks I know this is a somewhat narrow area of interest ....
Hello Jim,
Great post! Thank you. As one who hopes to try making and working in
these composite metals sometime in the (hopefully) not too distant
future I really appreciate your sharing this kind of hard-won --or
fortuitously gained as the case may be-- experience. Not a “narrow
area of interest” at all, IMHO, as I wager that many of us are better
for the knowing.
It was wonderful to meet you at the BMAC show last August and to see
your beautiful work in 3D rather than photos.
All the technical I have been able to access on making
mokume is sketchy in regard to combining various golds. As you
know, it is rather daunting to take thousands of dollars worth of
gold and make a billet that may fail - I can also understand the
reluctance on giving advice on how to make a billet using “thousands
of dollars worth of gold that might fail”.
Nevertheless, would you consider posting on this topic?
Or perhaps publish an article that could be downloaded for a fee?
I have been successful so far following your method of making mokume
and have gone as far as producing 24k gold/sterling silver billets.
Now I would like to produce some gold combinations but I would love
to have more
Here, here Jim. We work to inform folks about this problem every
day. I had a pair of sterling/copper rings in here a couple of years
ago. The owners were perefectly matched chemically. The copper on
both was etched out in just s few months. Under the microscope it
looked like a nitric acid etch. What is unusual is that was the only
rings I’ve seen in 20 years of selling the material. But I agree
fully with your letter. Bill
PS Have you seen the on the Mokume Design AVA awards?
Reactive Metals Studio, Inc.
PO Box 890 * Clarkdale, AZ 86324
Ph-928/634-3434 * Ph-800/876-3434 * Fax-928/634-6734
E-mail- @Michele_Deborah_Bill
Catalog- www.reactivemetals.com
Now a question-- would you still avoid all copper-based alloys
if the ring is to be lined with silver or gold?
Hi Noel,
I had the same question.
The Mokume bands that Joe bought for us this summer were apparently
gold-lined inside before shaping for a ‘comfort fit’ contour. Part
of the mokume gane was exposed at both inside edges.
The first couple of weeks we wore them, we noticed some green
discoloration on our fingers. Duh! I immediately recognized that
since the shakudo contained copper, it had to be leaching out of the
alloy! I contacted the jewelry store where the rings were purchased
and told the owner what was happening. He said that it shouldn92t be
a problem because the alloys are 18 Kt. gold. I suggested that the
copper in the shakudo was the issue and asked that he check with the
artist about it.
I did not like the look of the bands that had a full sleeve liner
with the gold edge showing on each side of the band but we loved the
rings (a ‘lightning bolt’ pattern) so I was hoping that the artist
could suggest another fix to correct the problem, perhaps a thick
electroplating on the entire inner surface.
When the jewelry store owner called back about 10 days later, he
said that the artist’s studio replied that the discoloration usually
abated after the rings were worn awhile and indeed, by then, it had.
I was still a little skeptical but decided to ride it a couple months
longer before pursuing anything further.
Recently, I noticed that the OUTER surface is showing some etching
as well. I’m certain of this because my band has a diamond mounting
and the etching is not apparent adjacent to the head but only on the
back of the shank where it contacts my palm and fingers.
I wish this very timely and helpful thread had been posted months
ago, but better late than never. At least now I know that the
process will lead to the eventual self-destruction of our lovely
bands!
Looks like I will have to become a tactful ‘difficult customer’
about it. I’d really appreciate any suggestions on how to handle
this. Anyone?
I find this post of yours to be extremely thoughtful, and useful in
concept beyond mokume. Not a “rant” at all, but a truly useful
“pointer”. I feel similarly about using soft stones, such as pearls
in rings. I always try to make sure that the client understands that
such materials will not hold up to everyday wear.
I was interested that you included silver in your list of
appropriate materials. I made sterling wedding bands 30 years ago
for friends—we were all poor undergraduates at the time, and I told
them that the sterling would not last, but they did not care, at the
time, and, indeed, they did not hold up well. (I recently made new
bands for them in 14K.) So, I am thinking that silver may be ok as
part of a mokume pattern, but not recoommended as a large component
of a wedding ring. What do you think?
Thank you for passing along that The question I have
though is what if you lined the ring? Would the shakudo (or even
copper for that matter) stand up to years of use (and possibly
misuse) if they were external to the ring with a gold or silver
liner?
Thanks for your kind words, it was a pleasure to meet you as well.
The problem with talking about golds is that they are more complex
alloys than sterling and each manufacturer has slightly different
“recipes” for their alloys so the critical about the
alloy characteristics (melting temperatures , ductility, hardness,
grain growth etc.) are different from one manufacturer to the next.
So unfortunately the empirical experiment is the best way to get
on how a group of alloys will go together. With that
being said if you treat a gold alloy stack just like a
copper/sterling one for the lamination part of the process you
should not have any problems with that phase. It is in the forging
(hot? cold?) , and heat treating (annealing time? temperature?,
quenching air? water? oil?) where the characteristics of the alloys
and their interfaces become too difficult to talk about in
generalities. Both Steve Midgett’s and Ian Ferguson’s books have
good info about technique. So read up and jump in and get your feet
wet. Make friends with your refiner and experiment.
Sorry I can’t be more helpful.
Jim Binnion
James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160
@James_Binnion
Member of the Better Business Bureau
Now a question-- would you still avoid all copper-based alloys
if the ring is to be lined with silver or gold?
Cameron wrote:
The question I have though is what if you lined the ring? Would
the shakudo (or even copper for that matter) stand up to years of
use (and possibly misuse) if they were external to the ring with a
gold or silver liner?
Yes copper alloys like shakudo, shibuichi, brass, bronze will all
corrode even if there is a liner of precious or corrosion resistant
(stainless steel or titanium) metal . In fact it is the presence of
the additional metals that cause the rapid corrosion of the copper
alloys. There is a galvanic “cell” set up when ever two metals are
in contact with each other and in the presence of an electrolyte
like salt water (sweat) the one with the greatest “anodic potential”
will corrode away while the one with the most “cathodic potential”
will be unaffected. The rate of corrosion will depend on lots of
factors but copper alloys paired with precious metals will all
corrode fairly rapidly under the conditions present on the human
hand i.e. warm, salty, and damp.
Here is a brief list of metals and their relative galvanic
potential. With any two (or more) metals in contact with each other
the one that is higher on the list will corrode. Some metals have
such noble properties that they will not corrode to any significant
degree like if you paired gold and platinum you would not see any
corrosion of the gold even though it is higher on the series than
platinum. In general the greater the separation of metals in the
list the greater the corrosion rate.
Corroded end (anodic, or least noble)
Magnesium
Zinc
Galvanized steel or galvanized wrought iron
Aluminum alloys
Low-carbon steel
Wrought iron
Cast iron
Lead
Tin
Copper alloy C28000 (Muntz metal, 60% Cu)
Copper alloy C67500 (manganese bronze A)
Copper alloys C46400, C46500, C46600, C46700 (naval brass)
Copper alloy C27000 (yellow brass, 65% Cu)
Copper alloys C44300, C44400, C44500 (admiralty brass)
Copper alloys C60800, C61400 (aluminum bronze)
Copper alloy C23000 (red brass, 85% Cu)
Copper C11000 (ETP copper)
Copper alloys C65100, C65500 (silicon bronze)
Copper alloy C71500 (copper nickel, 30% Ni)
Copper alloy C92300, cast (leaded tin bronze G)
Copper alloy C92200, cast (leaded tin bronze M)
Type 410 stainless steel (passive)
Type 304 stainless steel (passive)
Type 316 stainless steel (passive)
Silver
Titanium
Gold
Platinum
Protected end (cathodic, or most noble)
Jim Binnion
James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160
@James_Binnion
Member of the Better Business Bureau
I was interested that you included silver in your list of
appropriate materials. I made sterling wedding bands 30 years ago
for friends---we were all poor undergraduates at the time, and I
told them that the sterling would not last, but they did not care,
at the time, and, indeed, they did not hold up well. (I recently
made new bands for them in 14K.) So, I am thinking that silver may
be ok as part of a mokume pattern, but not recoommended as a large
component of a wedding ring. What do you think?
My main concern is rings that self destruct due to galvanic
corrosion. I do feel that sterling is a little too soft for long
term wear but in a mokume laminate this is not a problem because it
is combined with longer wearing materials. So I see silver as a
borderline material for wedding rings if it is properly protected it
will be fine. You cannot however protect the copper alloys from
corrosion short of temporary measures like plating which kind of
defeat the purpose of getting other colors into the mix.
Jim Binnion
James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160
@James_Binnion
Member of the Better Business Bureau
I did not like the look of the bands that had a full sleeve
liner with the gold edge showing on each side of the band but we
loved the rings (a 'lightning bolt' pattern) so I was hoping that
the artist could suggest another fix to correct the problem,
perhaps a thick electroplating on the entire inner surface.
There is no fix it will only get worse with time.
When the jewelry store owner called back about 10 days
later, he said that the artist's studio replied that the
discoloration usually abated after the rings were worn awhile and
indeed, by then, it had. I was still a little skeptical but decided
to ride it a couple months longer before pursuing anything further.
This is because the shakudo had corroded so far that your skin was
no longer in direct contact with it.
Recently, I noticed that the OUTER surface is showing some
etching as well. I'm certain of this because my band has a diamond
mounting and the etching is not apparent adjacent to the head but
only on the back of the shank where it contacts my palm and
fingers.
It will eventually corrode near the head as well but as you noted it
is not in direct contact with the skin
I wish this very timely and helpful thread had been posted
months ago, but better late than never. At least now I know that
the process will lead to the eventual self-destruction of our
lovely bands! Looks like I will have to become a tactful 'difficult
customer' about it. I'd really appreciate any suggestions on how
to handle this. Anyone?
Ask for a refund. It is a inappropriate choice of materials for a
ring.
Jim Binnion
James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160
@James_Binnion
Member of the Better Business Bureau
Would it be safe to say that mokume isn’t so appropriate for any
piece of jewelry that is in constant(-ish) contact with skin? ie;
ring, bracelet, watchband. But is generally well-suited for pendants
(although may have occassional contact), pins, earrings, bolos, etc.
that aren’t? This is a very interesting thread.
Would it be safe to say that mokume isn't so appropriate for
any piece of jewelry that is in constant(-ish) contact with skin?
ie; ring, bracelet, watchband. But is generally well-suited for
pendants (although may have occassional contact), pins, earrings,
bolos, etc. that aren't? This is a very interesting thread.
No that is not at all correct. Mokume is a technique not a material.
Certain materials that can be incorporated into laminates made via
the mokume process are inappropriate for use in rings especially but
also in other direct contact with the skin items. On the other hand
many of the materials used in the mokume process are perfectly
appropriate for use in rings and other items in contact with the
skin. The point is that care must be taken in choosing the right
materials for the laminate if it is to be used in rings.
Jim Binnion
James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160
@James_Binnion
Member of the Better Business Bureau
I think the only part of the glasses frame that is a problem is the
temple piece around and just forward of the ear. And this could be
mitigated by the use of clear heat shrink tubing applied to these
areas. Also the sheet I sent you has the sterling layer on the back
side so this will be the main point of contact with the skin so this
will minimize the corrosion.
Brian is currently making me a set of eyeglasses from a sterling and
shakudo flat laminate mokume sheet that I made. I have just seen the
first pictures of the progress today and they are looking great. I
cant wait to get them.
Jim
Jim Binnion
James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160
@James_Binnion
Member of the Better Business Bureau
Greetings all. I admit to not being very knowledgeable in this area
as I’m still a newbie but I do have a question I’d like answered. I
really could use an education on this topic. Is there any reason that
some kind of lacquer or clear acrylic substance couldn’t be painted
on these rings to eliminate the etching due to skin contact? I
understand the need to use appropriate materials in the initial
construction, as has been so well explained by Jim Binnion but, if
someone such as Noel already has a ring that she likes to wear,
surely there must be some form of stop-gap measure to slow the
etching process or stop it by precluding skin contact. I really
respect you folks’ opinions on these things because I’d like to avoid
such pitfalls if/when I dabble in such technical ideas. Jim I’ve
learned a great deal from your responses and expertise on a great
many topics and I thank you for sharing with us. I can only read so
much theory and I learn well from hands on effort but these topics
are something I probably wouldn’t have even thought of before trying
them.