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Argentium, Possible Contamination?


#1

Good Day valued Orchidians,

I have been working with Argentium Sterling Silver for about 2 weeks
which I purchased from a supplier listed on the
http://www.argentiumsilver.com (reputable). For the past few months
I have tried to educate myself by reading the Orchid archives,
Cynthia’s paper and Trevor’s blog. All are invaluable sources of
on this topic.

Up until today I have had a wonderful Argentium experience, mainly
doing small projects to get a feel for the metal. I have annealed,
fused, soldered, heat hardened, etc. I also did experiments with
Argentium and Sterling mixed. All has been wonderful until today.

I have a separate ceramic crop pot for my Argentium pickle (I use PH
minus/down). I also have separate buffs (tripoli and Zam) as well as
a separate soldering surface for my Argentium work.

Here is what happened:

I made some coils for a new bangle design I have been playing around
with. After making the coils I heat treated them and threw them in
the pickle to take off the slight yellow discoloration that occurs.

I made a prototype of my bangle with COPPER sheet and wire and then
wrapped my Argentium coils around the wire. Once I was satisfied
with my design, I removed the coils and decided to throw them back in
the pickle for a thorough cleaning and to my shock they turned black
(dark grey). Some were just black on one side (where they were
resting on the bottom of the pickle pot). I made a fresh pickle, used
plastic tongs instead of copper and the staining further spread over
all of my coils. I made another fresh pickle with Sparex just in case
the problem was the PH down pickle. There was no improvement.

My question are:

  1. After searching the Orchid archives I have determined that mixing
    copper and Argentium is a no-no but would the two metals simply
    touching each other have cause this blackening? What if a customer
    decides to wear an Argentium bracelet and a copper one at the same
    time?

  2. Should I not use copper tongs in my pickle?

  3. I also read that cleaners/degreasers and the liquid used in
    ultrasonic machines should have a neutral PH. Does this apply to
    pickle? Is PH minus/down considered neutral? Is there a recommended
    pickle for Argentium? Forgive the potentially stupid questions here.

  4. Last but not least, how do I remove this staining? I tried to
    polish it off but I can’t reach the inside of the coils. They have an
    antiqued look currently which is not my preference.

Any advise or suggestions are greatly appreciated.

Regards,
John


#2

Dear John,

I am not sure what the cause of the darkening of the silver is, but,
if the silver is indeed Argentium Sterling, I can answer question #4,
and tell you how to get rid of the dark color: Heat it with a torch,
being sure to keep the flame moving on and off the metal, so that
oxygen is present in the atmosphere around the metal, until it turns
white, and then pickle the metal. In fact, this is approximately what
I would do for this problem even if the problem had occurred with
traditional sterling silver (though traditional sterling would
probably not turn white until it had been pickled).

Interestingly, though, Argentium Sterling has an unusual property,
which is due to the germanium. This heating procedure, described
above, can be used to differentiate between Argentium Sterling and
traditional sterling silver . If you heat a piece of freshly abraded
AS next to a piece of SS, both bits of metal will turn black. If you
keep heating, being sure to expose the metal to oxygen by moving the
flame on and off the metal, Argentium Silver will turn whitish again,
while traditional sterling will stay black. The first time I saw and
realized this, I was amazed — it is so counter-intuitive to what an
experienced metalsmith expects! It shows how "oxygen hungry"
germanium is----what I think is happening is that the metal turns
dark when the copper on the surface has become CuO, cupric oxide.
Then, as the heating continues, the Ge, germanium, “grabs” the
oxygen from the copper, to form GeO2, germanium dioxide. The CuO,
having lost the O to the Ge, goes back to being Cu, part of the
sterling alloy, and the metal looks like whitish sterling again.
Germanium dioxide is the transparent surface of Argentium Sterling
that prevents oxygen from penetrating inside the metal, preventing
the formation of Cu2O, cuprous oxide, known most commonly as fire
scale, which is the darkening under the surface of the metal.

This property of Argentium Sterling is what I now recommend for
differentiating between AS and SS if you have both metals in your
studio, and there is confusion over which is which. As I keep working
with Argentium Sterling, I continue to learn. I recently updated my
article for the September issue of Art Jewelry magazine, which
includes color photos of processes and finished metalwork. I am very
pleased with the way that the editors I worked with (Hazel Wheaton
and Nanz Aalund) and the graphic designers, handled my article.

In terms of why this happened to your AS wire coil, it may remain
one of the many mysteries that we come across as we work with metal.

As to your other questions:

  1. I don’t think that this happened because copper and Argentium
    Sterling touched each other.

  2. Feel free to use copper tongs in the pickle. I use copper tongs
    most of the time.

  3. I don’t think your questions are stupid at all! I think that you
    can use whatever pickle you like for Argentium Sterling—PH
    Down/Minus, Sparex, citric acid, sulphuric acid----they all work, as
    far as I know. Your question about neutral ph is an interesting one.
    I’ll ask the scientists I know, and try to get an answer.

I would like to add a caution: I have received questions about
problems from metalsmiths who purchased silver from, or had castings
done by, companies that told them it was “the same as Argentium
Sterling Silver”. I advise being very careful about this sort of
thing. Because of patents, and the fact that both the formulas and
processes for manufacturing sheet and casting Argentium Sterling are
very specific, I don’t think that there is anything in the market
that is “the same as Argentium Sterling Silver”.

Meanwhile, heat that coil of darkened AS, and “trust the force” of
the germanium in Argentium Sterling!

Best wishes,
Cynthia

Cynthia Eid
http://www.cynthiaeid.com


#3

John,

how do I remove this staining? I tried to polish it off but I
can't reach the inside of the coils. They have an antiqued look
currently which is not my preference. 

Distilled water alone causes Argentium silver to discolor to a
slight pink copper to gray, depending on how long you leave it
submerged. I have found that freshly made pickle is more likely to
discolor the silver than aged pickle, again, it is probably the
distilled water. I use PH Minus sodium bisulfate and copper tongs. I
had two pieces made at the same time from the same silver with one
coming out of the pickle pink and the other not discolored at all
(?). I use hydrogen peroxide with pickle to remove slight
discoloration. I limit the amount of time to two to three minutes in
hot pickle and add baking soda to distilled rinse water (0.1grams of
sodium bicarbonate to 100grams deionised or distilled water,
according to Peter Johns). No point in limiting copper items from
your pickle pot because a lot of copper is released from the
Argentium silver into the pickle (pull some pickle out to a clear
glass container and you will see very blue liquid. Also, if you put
Argentium silver in fresh hot pickle in a clear glass container, you
will see a blue haze rising off the silver). You might try an ionic
cleaner to remove heavy discoloration. I have used the ionic cleaner
for heavily tarnished Argentium silver (but don’t know if tarnish is
the same as discoloration from pickle).

Hope this helps,
Nancy
www.psi-design.com


#4

Cynthia:

I spent a couple of hours completely cleaning my studio and bench
area, paying special attention to separating my Argentium from
everything else, especially copper.

Then I did as you suggested “Heat it with a torch, being sure to
keep the flame moving on and off the metal, so that oxygen is present
in the atmosphere around the metal, until it turns white, and then
pickle the metal.”

Initially I had the annealing steps in my head (don’t overheat, use
paste flux and a permanent marker as an indicator) While doing so
the metal was turning shades of light yellow/gold not white. I
pickled and repeated the procedure several times. There was
improvement. I would say the last time or two I was heating past an
annealed state which rendered a whiter color (which I noticed during
heating).

Cynthia, am I correct in assuming that your suggestion to heat the
Argentium “until it turns white” is beyond an annealed state?

The end result is that my coils are now clean! I showed them to my
wife (who saw them blackened before) and her words were “wow, they
turned white”! I had to grin at her description of the beautiful
color of the Argentium.

Prior to posting this question, I read a post about possible copper
plating of Argentium occurring while tumbling

http://www.ganoksin.com/orchid/archive/200603/msg01484.htm.

I thought this might be a comparable problem although my Argentium
was black not copper colored.

The troubleshooter in me would prefer to know what happened although
I am glad to have my Argentium back to normal. I trust you opinion
that the blackening didn’t happen just from the copper and Argentium
metals touching each other although this is the only logical
explanation I can come up with. Perhaps it was more than "touching"
as I was sliding the snug Argentium coils onto the copper wire which
may have caused some copper particles to abrade the surface of the
Argentium which in turn spread in the pickle?

As for which pickle to use, it would be nice to know which ones are
considered PH neutral and WHY a PH neutral pickle is suggested for
Argentium.

I look forward to reading your article in the upcoming (September)
Art Jewelry Magazine!

I am not only happy with the mysteries of working with this metal, I
embrace them. Each problem or hick-up brings investigation, a
solution and ultimately more knowledge.

It is an honor to have advice from those of you who have gone above
and beyond helping the ever growing group willing to learn about this
new metal.

I wonder if we can buy stock in Argentium?

Again my thanks to your generosity Cynthia,

Cheers,

John
A believer in the AS force

P.S. I incorrectly stated that I purchased my Argentium from a
company listed on http://www.argentiumsilver.com/ (I don’t think they
list suppliers)? I am confident that I am indeed working with true
Argentium and not a look alike as I purchased from one of the
companies Cynthia mentioned here on Orchid which is also listed on
http://www.metalwerx.com


#5

Note to those readers who have not been following this thread from
the beginning: this procedure is only for turning darkened metal
white again. (The wire coil was not clean when taken out of the
pickle.) In this case, I think that the silver darkened from being in
the pickle too long, or the pickle being too strong.

Initially I had the annealing steps in my head (don't overheat,
use paste flux and a permanent marker as an indicator) While doing
so the metal was turning shades of light yellow/gold not white. I
pickled and repeated the procedure several times. There was
improvement. I would say the last time or two I was heating past
an annealed state which rendered a whiter color (which I noticed
during heating). 

Usually, I would find that if the color lightened during annealing,
the pickling finishes the cleaning. Are you saying that it did not
come out of the pickle white?

Cynthia, am I correct in assuming that your suggestion to heat the
Argentium "until it turns white" is beyond an annealed state?

To be honest, when I have done this, I have not put the flux on, so I
did not have a temperature indicator. I’ve never had any problems
with the metal afterwards, though. I think it is best to heat at
annealing temperature longer, or repeatedly, as you did, than to
over-heat.

The troubleshooter in me would prefer to know what happened
although I am glad to have my Argentium back to normal. I trust you
opinion that the blackening didn't happen just from the copper and
Argentium metals touching each other although this is the only
logical explanation I can come up with. Perhaps it was more than
"touching" as I was sliding the snug Argentium coils onto the
copper wire which may have caused some copper particles to abrade
the surface of the Argentium which in turn spread in the pickle? 

Well, as we know, lots of surprising things happen when we work with
metal, and, when we are trying something new, even more crazy things
than usual occur! So, it does seem possible, but, I still think that
the darkened color came from over-pickling. This opinion is shared by
both Peter Johns-

the inventor, and Sam Davis-the chemical engineer at Stern-Leach
whose primary job is working with Argentium Sterling.

As for which pickle to use, it would be nice to know which ones
are considered PH neutral and WHY a PH neutral pickle is suggested
for Argentium. 

I’m not sure than anyone has looked into the PH of pickles. The PH
was discussed in terms of ultrasonic solutions.

Sam Davis pointed out that a too-strong pickle solution and/or a
too-long time in the pickle can turn both traditional and Argentium
sterling dark if the pickle is a Sparex/PhMinus/swimming pool acid or
sulfuric acid type of pickle. Interestingly, citric acid pickle and
phosphoric acid used as pickle do NOT turn silver dark if the silver
is “over-pickled”.

I look forward to reading your article in the upcoming (September)
Art Jewelry Magazine! I am not only happy with the mysteries of
working with this metal, I embrace them. Each problem or hick-up
brings investigation, a solution and ultimately more knowledge. 

That’s a good attitude!

It is an honor to have advice from those of you who have gone
above and beyond helping the ever growing group willing to learn
about this new metal. 

Thank you, John! It is an honor to be able to help in this way.

I wonder if we can buy stock in Argentium? Again my thanks to your
generosity Cynthia, 

You are most welcome! I am glad to have been able to help.

Best wishes,
Cynthia Eid
http://www.cynthiaeid.com


#6
Distilled water alone causes Argentium silver to discolor to a
slight pink copper to gray, depending on how long you leave it
submerged. I have found that freshly made pickle is more likely to
discolor the silver than aged pickle, again, it is probably the
distilled water. 

Thanks for that Nancy but I did not use distilled water in my PH
minus pickle, just regular tap water.

I limit the amount of time to two to three minutes in hot pickle
and add baking soda to distilled rinse water (0.1grams of sodium
bicarbonate to 100grams deionised or distilled water, according to
Peter Johns). No point in limiting copper items from your pickle
pot because a lot of copper is released from the Argentium silver
into the pickle (pull some pickle out to a clear glass container
and you will see very blue liquid. Also, if you put Argentium
silver in fresh hot pickle in a clear glass container, you will see
a blue haze rising off the silver). 

Normally I have only pickling my AS for a couple of minutes but when
my blackening occurred I changed the pickle TWICE and left the coils
in the pickle for about an hour each time (yikes). I surmised that
maybe I didn’t pickle them long enough in the first place and doing
so for a longer time would clean my coils which of course was not the
case. I will follow your process and limit the length of time I am
pickling.

Quotes from Cynthia:

Usually, I would find that if the color lightened during
annealing, the pickling finishes the cleaning. Are you saying that
it did not come out of the pickle white? 

When I went through the process of heating the silver, pickling and
rinsing with water/baking soda, there was improvement each time
however only SOME parts of the coils turned “white” out of the
pickle. I had to do the process several times to remove it all. Keep
in mind Cynthia that the coils were pretty black and there was lots
of wire to clean. I didn’t mention this originally but they were
"double coils" (specifically 28 gauge wire wrapped around 24 gauge
wire then this coil was wrapped around 24 gauge wire). Because the
wire gauge was so thin, I didn’t want to fuse them hence my decision
to do the heating process several times trying not to overheat.

Sam Davis pointed out that a too-strong pickle solution and/or a
too-long time in the pickle can turn both traditional and
Argentium sterling dark if the pickle is a Sparex/PhMinus/swimming
pool acid or sulfuric acid type of pickle. Interestingly, citric
acid pickle and phosphoric acid used as pickle do NOT turn silver
dark if the silver is "over-pickled". 

If the suggestion is that over pickling can cause discoloration then
I would say I TOTALLY over pickled my AS. I did some searching on
orchid for citric acid pickle and Trevor posted this link for anyone
interested:
http://www.touchmetal.com/workshop/citricacidpickle.html. Just in
case, I will switch to this instead of PH down although I have no
proof that this type of pickle was the problem.

Thank you to Nancy, Cynthia & Trevor for your help!

Cheers,
John


#7

In my earlier post I said “(0.1grams of sodium bicarbonate to
100grams deionised or distilled water, according to Peter Johns).”

I need to correct the statement I attributed to Peter Johns. He said
adding baking soda to deionised water prevented Argentium Sterling
from discoloration. He did not say baking soda prevented
discoloration in distilled water. I regret my misunderstanding and
apologize to Peter Johns.

I have found that Argentium Sterling silver granules in distilled
water discolor to slight copper pink to varying shades of gray after
3-5 minutes. I now limit a distilled water rinse to under one minute
but if discoloration does occur, I use a mix of hydrogen peroxide
and pickle to instantly remove it.

I hope this corrects any misI passed along.

Nancy
www.psi-design.com


#8
Initially I had the annealing steps in my head (don't overheat,
use paste flux and a permanent marker as an indicator) 

Hi all. While I haven’t taken the Argentium plunge yet, this
statement caught my eye. How do you use permanent marker as an
indicator of annealing temperature? I don’t have the luxury of
soldering/annealing in an area that can be darkened sufficiently to
see those subtle colors. I have long wished for some some substance
that could be placed on the silver to give an accurate visual
indication that annealing temp has been reached. Is Magic Marker or
Sharpie the answer? Is there something better? Thanks!

Allan Mason
www.silvermason.com


#9
How do you use permanent marker as an indicator of annealing
temperature? I don't have the luxury of soldering/annealing in an
area that can be darkened sufficiently to see those subtle colors.
I have long wished for some some substance that could be placed on
the silver to give an accurate visual indication that annealing
temp has been reached. Is Magic Marker or Sharpie the answer? Is
there something better? 

There are two excellent sources for Argentium sterling silver which
I am sure have been mentioned many times before. One is Cynthia Eid’s
technical paper found here:

http://www.cynthiaeid.com/ms-05-07.html

and the second is Trevor’s blog (from Touch Metals) found heee:

http://touchmetal.com/blog/argentium-blog.html.

To answer your question Alan, I found a slightly different version
of Cynthia’s paper which was reprinted by Rio Grande in which Cynthia
specifically mentions using a permanent marker as a temperature
indicator. Here is the PDF link (read under “Annealing”):

http://www.riogrande.com/images/ArgentiumSterlingSilver.pdf.

Here is Trevor’s reference for using a permanent marker on his blog
under “Little trick for annealing”:

http://www.touchmetal.com/blog/2005/09/little-trick-for-annealing.html

I spent countless hours reading from these two which was
invaluable to me (again my great thanks to them both).

Cheers,
John