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Brittle castings with de-ox

We just started casting de-ox silver with our Memco casting machine.
However, the de-ox castings come out very brittle, where as the
regular sterling and gold castings come out fine. Our casting
temperature is 1796 degrees Farenheit. After casting, we wait until
there is no red in the button before quenching. Do we need to mix
the de-ox with regular sterling (50/50) ratio? Is the casting
temperature too high? And ideas?

JoAnna Kelleher, owner
Pearl Exotics Trading Co., LLC
Phn (623) 845-0998
Fax (623) 845-0917

Hi JoAnna, If you are using united precious metals de ox sterling,
then, you have to allow the flask to cool for 20 minutes before
quenching in water… it is the exact opposit of regular sterling .
We have used this alloy since they first came out with it and have
never had brittle problems… also, which alloy of theirs are you
using? They have some alloys that are for special applications that
work differently. Please email me at if you
have any questions or find out what alloy you are using and I will
give you the best answer I can . Daniel Grandi

We do casting,finishing and many other things for people in the trade.

G’day JoAnna. Before I can give you any help on your DE-OX Silver I
must have the chemical composition. As a Material Scientist (
Metallurgist ) I need to know what the De-ox is made of. As in, what
Percentage Silver, What Percentage other components. With this
Knowledge I can tell you if you are stuck with a brittle material or
what to do with it. In most countries suppliers must on request,
supply you with Material Data Safety Sheets (MSDS). This will give
you a chemical composition of your product.

One Interesting bit of Information Sterling Silver Must contain 92.5
Silver and the rest Copper. If De-Ox Silver doe’s not comply with
the above then according to the Law you can not Hall Mark It
Sterling Silver as the Law States Sterling is 92.5 % Silver and 7.5
% copper.

Kind Regards.
Please Do not Hesitate to contact me at.
Michael W Kohlleppel
Art Tech Castings Australia.
@MWKohlleppel or

1 Like

The constituent in deox SS is Gallium…added in tiny amounts. The
law states 925 silver only. There is no requirement that it must be
all copper. The Gallium alloys are widely accepted as bona fide
sterling by most all the Symposium technocrats, as well as many of
the top producers of sterling jewelry worldwide…and in the ten
years or so since being patented, have never been legally challenged
by anyone. Doc Robinson Goldbarz

Hello Doc, Is the deox SS the same as “oxidation hardening silver
(hardenable silver alloy)”? OHS was manufactured by Johnson Matthey
Metals (#1715; item number) and is no longer available from them. I
am looking for a source for OHS. If Deox SS is not the same alloy,
and having missed the original question about it that you were
answering, would you please describe it’s characteristics (response
to heat, etc.). Thanks, Linda Kaye-Moses