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Argentium surface passivation heat treatment


#1

I have been working with Argentium for a couple of years and find
that I still polish and polish my work. I had read about heating it
in my oven at 250 degrees to activate the Germanium and decrease the
level of tarnish. However, I find that the instructions vary quite a
bit from 20 minutes at 250 degrees to up to 3-16 hours at 212
degrees. I tried heating it up to 250 for one hour. I used the Silver
polishing cloth recommended by Cynthia Eid and Rhonda Coryell. I
don’t really see much effect. Somewhat later when the sunshine cloth
is applied to any pieces, they still generate quite a bit of tarnish.
I used a pyrex dish, clean oven and oven thermometer. Are there some
tips to doing this that I am missing? Suggestions
would be appreciated. Thanks Barbara


#2

Hi Barbara et al

here are the instructions for Argentium. As verified by Peter Johns
the inventor of Argentium, Cynthia, Rhonda and Clare Felgate at at
Argentium International.

Heating at 250 degrees celsius for 2 hours heat hardens Argentium to
50% (the 50% may be 30% getting my maths checked by Clare) harder
than heat hardened sterling. This does not reduce tarnish or raise
the germanium. Piece needs to be pickled.

As there is some discolouring of the metal.

After heat hardening polish with blue hubble very expensive or
hyperfin very cheap. Hardened Argentium polishes better than non
hardened Argentium.

Blue hubble is the ultimate polish. Both hyperfin and blue hubble
will remove 1200 grit sand paper marks.

Now heat at 100 celsius for one hour this will “raise” the
geramnium. Piece comes from oven with the same polished finished that
it went in with.

There is some confusion out there re Argentium unless you read
Cynthia Eid’s and Argentium International’s instructions but that can
be hard work for the non-scientist. Read them slowly and carefully
because they are really excellent.

That said I am writting a quick start guide for Argentium, getting
it checked by the experts at the moment.

all the best
Ricard


#3

After you are done polishing and cleaning the item. Put it on a
stainless steel cookie sheet in an oven or a clean kiln shelf in a
kiln at 250F for 15minutes. That is it, it works! Yes I have heard
260F for 20 minutes that works also. This is all there is to it.

A lesson on silver, and almost every sterling product. No matter how
cleanand polished any item is. It will always cause a polishing
cloth to pick up black or grey color.

That is not tarnish that is the nature and character of the metal
Silver.

Sessin Durgham
Rio Grande Technical support


#4

Hi all

I posted There is some confusion out there re Argentium unless you
read Cynthia Eid’s and Argentium International’s instructions but
that can be hard work for the non-scientist. Read them slowly and
carefully because they are really excellent.

Should mean by non-scientist some one who can’t read a recipe or
follow a lawn mower manual. Who work out how the hell the high tech
washing machine works.

All the best
Richard


#5

Hi Sessin and other argentium users.

Where did you get this info. Argentium International and Peter
Johns, the inventor of argentium say 250 F should be for one hour.

Also with argentium it should be heat hardened at 250 C for 2 hours
before polishing.

Heat hardened argentium polishes better than not hardened argentium.

Also argentium should NOT be put on a stainless steel tray cross
contamination can occur.

Use a pyrex or such oven dish.

If you are right about the time it would save electricity. But put
some science behind it. Please.

all the best
Richard


#6

Question. Must the metal be completely annealed before heating? I
believe Iread that somewhere.

Judy in Kansas, where the first football game of the season occurs
this evening. Much cheering!!


#7
Are there some tips to doing this that I am missing? Suggestions
would be appreciated. 

HI all, After seeing the reponses to this question, I can see why the
person who asked about this is confused about the instructions.

I also appreciate Sessin pointing out that a polishing cloth will
ALWAYS pick up black from silver, even when the silver is clean.
That is not a test for tarnish. Your eyes test for tarnish.

-I think that some of the different times and temperatures come from
the fact that this is a relatively new alloy, so there is constant
experimentation and changes to the recommendations. I keep updating
my handouts.

-A second source of confusion is that we need to remember that this
is an international forum. Some countries measure temp in C, and
Some in F.

-A third source of confusion is that there is more than one "right"
way. That is the nature of jewelry and metalsmithing, and one of the
sources of discussion on this forum.

-Another reason for the different answers is that there are two
kinds of heating. BOTH processes increase the tarnish resistance,
since any temp over freezing encourages germanium to grab the oxygen
from the copper and silver.

  1. If there are no stones at risk, I recommend heating to harden the
    AS, which will also excite the germanium, creating germanium oxide,
    which prevents oxygen from reaching the surface of the AS, thus
    preventing tarnish. If there will be stones, I recommend hardening
    before setting stones. Prongs and bezels will be less hard than 14K.
    Personally, I use fine silver for bezels in these cases.

  2. if all you want to prevent tarnish, because you had to do a lot
    of polishing after setting, or some other reason, you can use lower
    temperatures. The longer the time, the more the germanium gets
    excited, and the greater the tarnish resistance.

There are are a range of times and temperatures for these
procedures, which allows us to do it quickly in a kiln, or more
slowly in a toaster oven (or kitchen oven).

I will repeat here excerpts of the info that is on the handouts I
give at my workshops, which I also have posted on my website, and in
the docs of the facebook group for Argentium.

HEAT TO INCREASE THE TARNISH RESISTANCE

The higher the temperature, the more excited the Germanium atoms
get, and the thicker the layer of germanium oxide that is formed.
(Germanium oxide is invisible to the naked eye. GeO2 prevents oxygen
from passing through silver, thus preventing tarnish and firescale.)

  • If stones have been set, then use any heat that is safe for the
    stones to encourage the creation of germanium oxide. It is ideal to
    heat at 250 F (121 C) for twelve hours, but even 100 F for an hour
    is helpful. These temperatures do not usually cause discoloration.

  • HARDENING is not a requirement for AS, but it is an option that
    will make the metal sturdier, while increasing the tarnish
    resistance at the same time.

o AS can be hardened by heating for two hours at 580 F/288 C. Air
cool afterwards.

o If a kiln is not available, a toaster oven can be used for 3 hours
at 428 F/220 C

o The alloy will not appreciably lose its hardness if left in the
oven an hour or so longer.

o Do not enclose the Argentium[tm] Sterling when heat-hardening.
Exposure to oxygen is needed to create the germanium oxide that
prevents tarnish.

o The hardening process will not have any harmful effect on fine
silver, sterling silver, gold or copper alloys that are used in
combination with Argentium[tm] Sterling Silver. Discoloration can be
removed with pickle.

o Should the need arise, the alloy can be annealed and then
re-hardened.

o Pickle to remove any oxides formed by heating

o Re-brighten the surface if necessary, by lightly repeating the
final finishing step (lightly rouge, or use an Argentium Silver Care
Cloth, or re-tumble briefly, or brass brush with soapy water,…)

PATINAS

Any chemical normally used to darken silver will work on Argentium
Sterling. Use your normal procedures. It is possible that it might
take longer than traditional SS, or need a slightly stronger
solution.

TARNISH RESISTANCE

Neither pure silver, nor any silver alloy is tarnish-proof.

With heat however, we can make Argentium Silver highly
tarnish-resistant.

ADD THIOL to the surface for additional tarnish resistance.

This chemical seems to bond with AS, to prevent tarnish.

Thiol is in Argentium Silver Care Cloth, Goddards Long Shine Silver
Cloth and polishes, and Tiffany mitts.

Cynthia Eid
Cynthiaeid.com


#8
Put it on a stainless steel cookie sheet in an oven or a clean kiln
shelf in a kiln at 250F for 15minutes. 

Might want to check that temperature, I believe it is 250C not 250F.

James Binnion


#9

Hi all

good post from Cynthia just one point

final finishing step (lightly rouge, Peter Johns the inventor of
Argentium told me not to use rouge as the iron oxide it contains
can lead to tarnish with Argentium. 

As polish’s particles imbed into the metal being polished.

Hyperfin or blue hubble are very good for Argentium.

I heat harden Argentium at 250 C for 2 hours. Pickle and polish,
Peter Johns told me heat hardened Argentium gets a better polish than
non-heat hardened Argentium. I have found this to be true. Then I
"raise" the germanium by heating for 1 hour at 100 C.

Heat hardened Argentium works with a hardness like 18 kt yellow
gold. So I work Argentium before I heat harden it.

Annealed Argentium is softer than sterling.

I have set lab grown sapphires, rubies, spinels, alexandrites and
CZs into solitaire bezel rings and then heat hardened.

Put piece in cold oven turn on (no thermal shock to stone) when
reaches 250 C leave for 2 hours. Turn oven off and let cool in oven.

Pickle in salt and vinegar. As I don’t know what safety pickle would
do to stone.

Give final polish and then “raise” the germanium at 100 C for one
hour.

Piece comes out of oven as shiny as it went in.

all the best
Richard


#10

Hi all I got some info from Clare at the Argentium helpline.

I have spoken to Peter Johns about hardness - he has advised that
heat >treating standard sterling will achieve approx. 65HV whereas
heat treating Argentium will achieve approx. 100HV. By work
hardening the Argentium you can achieve between 150-180HV. 

Can some one put these into percentages.

So as a percent how much harder is heat hardened Argentium over heat
hardened sterling?

How much harder is work hardened Argentium over heat hardened
sterling?

thanx to the maths dudes
all the best
Richard


#11

Hi Cynthia and James and others,

This raises some questions for me. How thick might the germanium
oxide layer be? If worn jewelry now has micro scratches or just
general wear through the germanium oxide layer in spots might there
be uneven tarnishing in those places? Is the germanium evenly
distributed throughout the alloy so that if there is wearing away of
the original layer it can be renewed by additional heat treating
down the road? If so, is this a practical solution for an
owner/wearer of the jewelry (I’m thinking more of rings and bracelets
here)? I suppose that this alloy is new enough that accumulated field
experience may not yet tell us the answers. Or, perhaps the
developers of the alloy have done some testing to give us the
answers.

Dennis F


#12
HEAT TO INCREASE THE TARNISH RESISTANCE The higher the temperature,
the more excited the Germanium atoms get, and the thicker the layer
of germanium oxide that is formed. 
(Germanium oxide is invisible to the naked eye. GeO2 prevents
oxygen from passing through silver, thus preventing tarnish and
firescale.) 

Two comments first oxygen does not cause tarnish, it is a reaction
between sulfur and silver forming silver sulphide. Silver does not
from a stable oxide from just contact with oxygen at room
temperature. It will form oxides at elevated temperatures but it
disassociates upon cooling.

Second While Argentium is tarnish resistant it is not tarnish proof.
The germanium oxide will slow the tarnish reaction it will not
totally prevent it. No high silver alloy is tarnish proof. If you
can patina it with liver of sulfur it will tarnish.

Jim
James Binnion


#13

Hi Judy,

It is not necessary to anneal before heating to harden. (It is
definitely not needed if you are just using a lower temperature to
increase tarnish resistance.) Annealing before heating to harden
will produce a somewhat greater hardness than if the AS is a bit work
hardened before the heat hardening procedure. Personally, I do not
bother with annealing, as I find the hardness produced by heating to
be more than adequate.

My understanding is that annealing is more important for heat
hardening traditional SS.

Cynthia Eid
Cynthiaeid.com


#14
Put it on a stainless steel cookie sheet in an oven or a clean
kiln shelf in a kiln at 250F for 15minutes. Might want to check that
temperature, I believe it is 250C not 250F. 

Sorry I thought you were trying to harden it which is the 250 C
number.

James Binnion


#15

Thanks for such a rapid response! I love AS and am especially
enamored of their solders. Judy


#16

Hi all

The hardness figures for Argentium I was quoting were for a single
stage heat treatment using a domestic oven.

I have found heat hardened argentium to be as hard as 18 kt yellow.

In Australia jewellers are using Argentium rather than sterling,
easier to work and no fire scale.

I post about Argentium because after 25 years of silver smithing I
find it superior to sterling.

I get nothing for these posts not even a T shirt LOL.

All the best
Richard


#17

I don’t understand this Argentium craze.

As I understand it, this metal is “tarnish resistant” So imagine a
ring set with an opal.

You heat up the ring to bring out the germanium layer and then set
the opal.

Six months later the ring has some tarnish on it, so you polish it.

The germanium layer is gone.

You can’t heat up the ring again because you might trash the opal.

So it is just the same as normal silver? I mean, it still tarnishes
eventually, so what’s the big deal?

Hans Meevis


#18

perhaps the developers of the alloy have done some testing to give
us the answers.

Please see Wikipedia http://www.ganoksin.com/gnkurl/ep81k0

No. 6 Inside Argentium silver - How does it work?

Click on the photograph and it will enlarge.

Peter Johns


#19
oxygen does not cause tarnish, it is a reaction between sulfur and
silver forming silver sulphide. 

No high silver alloy is tarnish proof. Both definitely true. I had no
intention of making false claims. This is a case of my generalities
causing confusion. That’s part of why I keep re-writing my
handouts----trying to be clear & succinct.

Cynthia Eid
Cynthiaeid.com


#20
This raises some questions for me. How thick might the germanium
oxide layer be? If worn jewelry now has micro scratches or just
general wear through the germanium oxide layer in spots might
there be uneven tarnishing in those places? 

It is not that thick and certainly can be scratched off. The upside
is areas that are under constant abrasion like the high spots on
rings don’t typically tarnish in wear. With time the GeO2 will
reform and some level of protection will be achieved. I don’t really
see this as a big problem.

Is the germanium evenly distributed throughout the alloy so that if
there is wearing away of the original layer it can be renewed by
additional heat treating down the road? 

Yes.

If so, is this a practical solution for an owner/wearer of the
jewelry. 

Probably not by the owner, the maker certainly could offer a
re-passivation service. Not sure it would be needed though.

James Binnion