Hi all It’s been a busy while since I participated. I have been
experimenting with casting in the new de-ox silver alloy available
from Indian Jewelers supply. Not only does this 925 alloy not
tarnish, there is also no firescale to deal with after casting and
soldering. It comes out of the flask with a bright finish, similar to
bead blasting. It takes a great polish and my finishing time was cut
in half, well worth the extra couple of dollars per ounce. I soldered
some findings to these pieces and found that a boric acid and alcohol
dip, with some Prips flux on the solder spots, does just as well as
the paste solders usually used with silver – without the mess. The
casting was smooth, no porosity in these six 3 gram pieces. The metal
seems a bit soft though. I haven’t tried rolling, forming or work
hardening it in any way, nor have I yet experimented with slow
cooling it to produce a harder end result. I wonder if anyone out
there has rolled this stuff into sheet, made wire, planished it etc…
Is this stuff too soft for rings? Can it be heat-hardened? Are there
other kinds of de-ox silver out there? I am looking at casting some
rather large (9 troy oz.) pieces with it. Any experience there? I’d
be grateful for any input.
Hi Tom, I have been using the De-ox silver and gold alloys from
United. As far as the silver alloy goes; I have successfully rolled it
but it is softer than the traditional silver/copper alloys. Isn’t it
great to break the casting out from the flask and see bright shiny
silver as opposed to the dull black stuff? The non-ox gold alloys are
terrible for rolling or drawing. They tend to crack after just one or
two passes through the mill. I learned this lesson the hard way with
over an ounce of 18k. Oh well, I can always use it to cast with. These
alloys can successfully be heat hardened, but they will still not be
as hard as regular alloys. Ken
Hi Tom- I have a lot of casting in my designs. I just recently
switched over to de-ox silver for all the pieces and also found that
it is a bit easier to clean up and does have a much brighter look
when it comes out of the casting. I haven’t followed it to to
customer/end -user to see about how fast and if it tarnishes more
quickly . ( I have a lot of texture in my work and if the customer
does not keep it polished, it doesn’t look great.) It is definately
softer to work with. I use Pripps flux to coat the piece before
soldering still. Have not worked with the sheet or wire to test that
out, and would also like to hear about other people’s experiences
with it. I do not do my own casting,so I cannot give you an
experience with that. It seems though that if you mix the de-ox cast
pieces with regular silver sheet, findings, and solder that they
should tarnish at different rates, especially the solder joints.
Alexis
You should be aware that some of the non tarnish silvers are being
made with cadmium as a part of the alloy. Most vendors will not tell
you the contents of the alloy but there have been several reports of
cadmium being used. It is bad news to melt and breathe the fumes from
cadmium containing alloys so be careful with these alloys.
Jim
@jbin
James Binnion Metal Arts
4701 San Leandro St #18
Oakland, CA 94601
510-533-5108
Tom, I haven’t used the deox from indian supply but I have been using
United Precious Metals master formula for silver for a couple of
years now. It is also a deox formula. I get the same great results you
got casting. Forging however is another problem. The metal tends to
work harden faster and you get cracks in the ingots if you are not
careful. I usually use a sprue button a couple of times and then
recycle it for forging or wire. Seems to work ok. My pieces don’t seem
to oxidize in the show case quite as fast as the other alloys do. Good
stuff in my book. Frank
I cast alot of silver, but have not used the de-ox. The main reason
that I’ve not tried it is that Rio Grande has a warning on theirs that
you can NOT plate it, using cyanide-based solutions. Does anyone know
if this is true (must be at least true of Rio’s silver)? I’d love to
skip the initial clean up of the castings and can’t imagine what it’s
like to see shiny silver pieces, but I need to be able to plate if I
want. hmmmmmm new slogans, “from the flask to you”, "castNship.
Bud Cravener
You should be aware that some of the non tarnish silvers
are being made with cadmium as a part of the alloy. Most vendors
will not tell you the contents of the alloy but there have been
several reports of cadmium being used. It is bad news to melt and
breathe the fumes from cadmium containing alloys so be careful with
these alloys.
That is a big reason why I don’t like not knowing what is in my
alloys and why I’m continually blowing my time on alloying my own
metals. Shouldn’t there be some kind of a metals disclosure law that
forces refiners/metals suppliers to claim what is in their alloys? It
isn’t like they’re going to be giving up their secret to the
competition anyway; not as long as one can pay $40 for an elemental
analysis and know what is in it.
Dear Tom, I have been casting the deox sterling for about six years
now. As soon as it came out we switched. The reduction in firescale
has been the main reason. We still tumble and polish as usual. It has
a slightly whiter look than regular Sterling. The main noticeable
difference is that is is much more brittle than standard Sterling. You
will notice it when rounding rings up on the mandrel after casting.
The bottoms where the sprus attach may crack. Not always but most of
the time. We try to make the shank bottoms a lot heavier to
compensate. It gives the customer a heavier ring in any event. Most
of my casting are pendant that weight betweed one and three
pennyweights. The pieces this size cast well. There is on occasion
some very fine surface firescale but it does polish out. You can also
cast the deox a lot colder. A heavy 15 dwt ring is spin cast at 500
degree F. The finish is very clean. I still fabricat out of regular
Sterling. I haven’t seen any sheet made from the deox unless you make
it yourself. And by making the stock yourself you burn off most of the
deox. You can’t strip or bomb the material because of the reduce
copper level in the alloy. It looks more frosted and not bright. We
burnish to get the bright look instead and it’s not as toxic as the
stripping or bombing. You do have to melt at a higher temperature
either with a torch or with a electro melt furnace. If you furnace
melt the metal temperature should be 1950 degrees F before pouring. We
do cast some regular Sterling, but about 90% is now deox.
My caster, Larry Paul in Philadelphia, uses the de-ox silver (don’t
know thw formula) and I am very happy with it. I like the color
better, and it isn’t as likely to turn the customer’s hand black.
It’s softer, but that’s just another design consideration.
You may be able to rhodium plate the de-ox by first plating an
undercoat of acid-based gold plating solution–that is if the cyanide
solution won’t take but the acid based stuff will. I also wonder if
you can then add a layer of cyanide base gold plate to the rhodium.
Sounds like a lot of trouble, but I wonder. Thank you all for the good
input on the de-ox silver. I’ll keep you posted on what else I can
find out.
It is bad news to melt and breathe the fumes from cadmium
containing alloys so be careful with these alloys.
Most (if not all) manufacturers will provide free of charge a MSD
sheet on any alloy you buy. It won’t give you exact percentages, but it
will tell you if the metal has cadmium in it or not. Ken
Hi everyone In Todd Hawkinsons posting he mentioned that casting large
silver castings at 500 degrees F. Does that apply to de-ox silver
only or does that go for regular sterling, maybe even for gold? What
is the rationale for casting at such a low flask temperature? I’ll be
casting a series of 9 ounce pieces and have a large capacity nitrogen
atmosphere vacuum machine available to my use. I suppose the large
volume of slowly cooling silver in the flask could break down the
plaster. I did cast one piece at 950 degrees in regular sterling, and
it had some worm holes.
Thanks for all the help
Tom Tietze
The Artisan Workshop
All sellers are required to provide MSDS forms for any potentially
hazardous materials, plus if used for a business a MSDS file is
required. Yes, even WalMart and such must and will provide MSDS in the
US. (By the way to OSHA flour and cooking oil are Hazardous Materials,
I’ve read their MSDS forms!)
Dear Tom, In the days before any deox metals the rule of thumb was to
cast the flask as cold as possible. The temperature was determined by
the object detail first and the type of metal second. The heavier the
object the colder the flask. When cold flask casting, I have the best
luck with spin casting. This forces the metal into the cavity and then
as quickly as possible solidifies the metal. If you are casting a
large object like you describe it sounds like a foundry pour more than
jewelry casting. Maybe a foundry person could help?
Bud: you can get bright silver castings using zinc which deoxidizes
the metal too and I’ve done this. You alloy zinc and fine silver 50/50
and toss in a small pea size after the metal is melted. You’ll get a
colored flame and stir it in and let it fly. I just found an old
jewelry book from 1910 that mentions casting in the middle ages and in
silver casting the author mentions throwing in a chunk of “spanish
brass,” whatever the heck that is. I suspect the zinc in the brass was
the reason why as well as the copper to make sterling. The only
problem with the zinc method is the inital alloy is difficult to make
as the zinc burns too fast and if you don’t cast quick enough the
melt sucks oxygen in again. I’m now using United’s de-ox S-88 alloy
which was recommended by Dan from Racecar Jewelry who casts alot of
silver. The beauty of the stuff is it casts bright, you can re-use
the buttons without adding anymore alloy and it still stays bright.
The metal does seem softer and you CAN oxidize/antique despite what
someone else said. Its NO guarantee against pits as I still get them
and despite reading every book and asking all of you they still show
up. But I do recommend the S-88 alloy and its not expensive if you buy
the alloy only…Dave
Dave, Have you tried the plastic flask liners made by vac-u-cast?? I
use them withe the same s-88 united master and they really help the
pousority problem. they are a plastic web that fits around the inside
of the flask. They sell them for vacume casting but I use them for
centrifuge also. they helped me. Frank
Hi Dave, Try some powdered charcoal casting flux. It will usually
clean the metal and the porosity right up. Skip
Skip Meister @Skip_Meister
Orchid Jewelry Listserve Member
A day without sunshine is like night!
N.R.A. Endowment
"No man’s life, liberty or fortune is safe…while our legislature is in session."
Benjamin Franklin
Hi Dave, Try some powdered charcoal casting flux. It will usually
clean the metal and the porosity right up. Skip
Skip: is this something you buy or do you just powder some charcoal?
My instruction sheets says to flux with boric acid for the de-ox
silver. How you doing these days anyway? Dave
