My friend Shana Kroiz from the Md Inst of art is working on a
commission and she was asking me about all of the options for
blackened metal in a ring. The project is an engagement ring and it
has yellow gold on the side rails and under the main ring.
Shokudo is beautiful but it is a copper base alloy and I know it
will not last. steel and iron type metals have a chance of developing
rust if left in humid atmospheres. how about cobalt steel, I know
that
tech forms casts it, but I have never worked with it. I am not in
love
with blackened palladium and I have really never explored how it is
blackened. Emamel cant be sized
So I always end up back at the tried and true sterling with a rough
finish then dipped in liver of sulpher.
When I do a wedding ring I like to look the customer in the eye and
let them know that it is possible to size the ring up or down alittle
bit in the future.
There are only three colors of workable metal: yellow of gold (even
“green” gold is really yellow), red of copper and everything else is
some shade of grey. None of them are black. Yes there are the group
of unworkable exotic intermetallics like purple gold but they are
not really suitable for jewelry use except as stone like objects set
in other metals and none of them are black either. All other colors
are surface coatings, whether they are corrosion products like
patinas, oxide films, paint like coatings, plating, high tech CVD or
PVD coatings they all suffer from durability issues to varying
degrees. None are really suitable for high spots on rings, the
abrasive abuse of day to day wear is just to hard on them for long
term survival. The high tech CVD and PVD coatings that are on some
european watches and jewelry showing up with are probably the best
coatings available but you will probably not find anyone willing to
do just one ring and they still wear off eventually. On low areas I
think you can find several viable solutions. But in terms of
longevity and repairability on gold I am not sure you can beat black
enamel paint in the low lying areas.
Jim
James Binnion @James_Binnion
James Binnion Metal Arts
To blacken silver & it does not have to be a dull finish, a trick
with gold is to use a piece of steel & dip the steel into the Pariser
oxide.
To get best result heat the piece up, use boiling water or a torch
but it must be HOT! Then you have a small container with the Pariser
oxide & just dip the piece in, it will not last forever but is much
better than sulphur.
I also use Black Rhodium, it is complicated but it works on gold, to
resize you would be better to remove it before heating up.
steel and iron type metals have a chance of developing rust if left
in humid atmospheres. how about cobalt steel
I have had good experiences with oxidizing stainless steel (316
type) after a medium bead blast surface has been applied, this holds
up extremely well if the oxidized surface is below the wearing
surface. You will not experience rusting with this alloy of
stainless.
More info can be found in previous post -
This does not address the issue of sizing a stainless ring with gold
around it, but it is one of the blackest surfaces I can achieve with
stainless that is comparable to oxidized silver.