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
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 Metal Arts