Back to Ganoksin | FAQ | Contact

Shakudo ring durability and sizing


#1

I would like info and advice about using shakudo with a mountain
design continuous around a 14kt sleeve with 14kt sides that are
higher than the center by about 1mm. Durability and sizing are my
concern. The shakudo center band would be between 4 and 5 mm.

Thanks.
Richard Hart G.G.
Jewelers Gallery
Denver, Co.


#2

Richard I do not think that the 1mm inset will be enough to keep soft
finger skin from touching the copper. Certainly it would not be
protected from sweat, oil and other body fluids. All which could be
acidic and etch the shakudo and/or discolor the skin. The patina
color would most likely be unstable. There will, of course, be a
solder line unless you form a seamless band and don’t size it. Bill

Bill, Deborah, Michele & Sharon
Reactive Metals Studio, Inc
928-634-3434, 800-876-3434, 928-634-6734fx


#3

This is probably not a good idea on a ring. The shakudo besides
being almost as soft as pure copper will set up a corrosion cell due
to its contact with the gold and it will dissolve away. This can
cause serious damage to the shakudo in just a few years. I have some
photos of a 18k and shakudo ring I made where the shakudo is
virtually all gone after 5-6 years

James Binnion
James Binnion Metal Arts


#4

Richard,

I would be concerned about pH and etching above all. You could
however make a plaque using gold foil as a bezel to back the shakudo
and as such keep it from contacting the skin of any potential wearer.
In fact this month’s Rock and Gem magazine has a project in which the
craftsman used metal foils to do exactly this. It looks as though the
stones he used were cast in place with gold surrounding a silver
baking plate. Yours would be adapted to have the shakudo ( I’m
guessing you want it for heat coloured variance in the purple hues
of mountains…or not!) surrounded by some high karat gold that you
have rolled out and fused to the shakudo alloy. It will work
beautifully- I just had a similar discussion with someone else
regarding a similar problem and how to solve it, then the article
appeared mirroring the solution- funny how spontaneous generation
works in that way…I would try it You’ll get a similar result to
your first conceptualisation but avoid the skin contact that could be
the ruination of the piece a year or so down the line, or sooner if
the person is an heavy sweater, or swimmer…rer


#5
I would be concerned about pH and etching above all. You could
however make a plaque using gold foil as a bezel to back the
shakudo and as such keep it from contacting the skin of any
potential wearer. 

It has nothing to do with skin contact with the shakudo. Backing it
with gold foil or soldering it onto a gold band will not achieve any
form of protection. The problem stems from the fact that when you
connect two different metals together you set up a small battery.
When you add an electrolyte by getting it wet with sweat, water from
the tap, pool, bath, ocean, etc you complete the connection and
current will flow. This is called a galvanic reaction it is the
basis for how batteries work. One metal will be more negative or
cathodic (gold in this case) and one will be more positive or anodic
(shakudo) and the more anodic one will dissolve just like you had it
set up in a plating bath. This dissolving is called galvanic
corrosion. The speed of the reaction depends on how much potential
difference there is between the pair and some environmental factors.
But between shakudo or most other high copper alloys and gold the
reaction is fairly fast as there is a fairly significant voltage
developed in the pair.

Because it is in a ring there will be a problem because most folks
get their hands wet many times a day and the ring will remain damp
for fairly long periods of time. It is the presence of water and salt
from the skin that allows the rapid corrosion to occur. In other
forms of jewelry in most cases you do not have as much contact with
electrolyte solutions so the galvanic action is so slow that you
will not notice it. If your client swims a lot with jewelry on then
this can be a problem.

This always occurs whenever two metals or even two different alloys
of the same metal are connected together. But the more noble the
metals The less corrosion potential there is, so even though there is
a current set up between silver and gold the silver does not dissolve
to any significant degree in the time scale of its use as jewelry.

James Binnion
James Binnion Metal Arts