Back to Ganoksin | FAQ | Contact

My silver is not fine

I’ve made some bracelets of braided 22ga .999 fine silver wire with
balls fused at the ends. In fusing the balls, the full hard wire was
annealed to dead soft for about 3/4" at either end of the bracelets.
Both reading and experimentation suggested that fine silver does not
work harden appreciably, so I took the pieces to a local shop with a
kiln. I had the shop heat the pieces to 600-650 degrees Farenheit
for one hour. One major overcharge later, all my work is completely
dead soft and utterly unsalable.

What have I done wrong, and can I recover these bracelets?

-Michael Balls

    I've made some bracelets of braided 22ga .999 fine silver wire
with balls fused at the ends.  In fusing the balls, the full hard
wire was annealed to dead soft for about 3/4" at either end of the
bracelets. Both reading and experimentation suggested that fine
silver does not work harden appreciably, so I took the pieces to a
local shop with a kiln.  I had the shop heat the pieces to 600-650
degrees Farenheit for one hour.  One major overcharge later, all my
work is completely dead soft and utterly unsalable. What have I done
wrong, and can I recover these bracelets? 

600-650 degrees Farenheit (almost 350deg C) is the temperature at
which fine silver anneals. So what happened was predictable.

Brian
Brian Adam
Auckland NEW ZEALAND

 600-650 degrees Farenheit (almost 350deg C) is the temperature at
which fine silver anneals. So what happened was predictable.

That’s great for the first part of the question. How about the
second part? Can this bracelet be saved, and how?

Betty

  600-650 degrees Farenheit (almost 350deg C) is the temperature at
which fine silver anneals. So what happened was predictable. 

Not to me. My research suggested that 600F was the correct
temperature to achieve full hardness in fine silver. Obviously my
research was badly mistaken. I already know that the silver has been
annealed; what would be really helpful is if somebody could offer
the correct procedure for hardening fine silver.

 Can this bracelet be saved, and how? 

Try tumbling it overnight-- or even longer, if necessary (with steel
shot).

–Noel

Hello Michael,

I don’t have any first hand experience with precipitation hardening,
but I have read a very informative article on the subject by Gary
Dawson in AJM Magazine.

You can find the article here:

Although the author does not provide instructions for hardening fine
silver, he does describe the process for sterling silver. If the
procedure for fine silver is the same as it is for sterling, you
performed only the second part of a two part process. Quoting from
the article:

      It is recommended to solution treat sterling silver at 750C
      to 760C/1,382F to 1,400F for 30 minutes, quench immediately,
      and age for one hour at 300C/572F. The hardness of the
      sterling alloy can be effectively doubled with this process,
      from HV 60 in the fully annealed state to HV 120. 
      The only problem posed by this process is that the solution
      treatment temperature is above normal soldering temperatures
      for sterling, so only articles with no solder can be treated.
      Soldering after hardening sterling will over-age the material
      dramatically to the point of nullifying the hardening effort. 

Since the joins in your bracelet are fused and not soldered, you
needn’t worry about Dawson’s cautionary note. I would do some more
research, though, to find out if the procedure or temps would be
different for fine silver before subjecting your bracelet to any
further treatments.

Hope this helps,
Daniela Muhling

     600-650 degrees Farenheit (almost 350deg C) is the

temperature at which fine silver anneals. So what happened was
predictable.

   Not to me. My research suggested that 600F was the correct
temperature to achieve full hardness in fine silver. Obviously my
research was badly mistaken. I already know that the silver has
been annealed; what would be really helpful is if somebody could
offer the correct procedure for hardening fine silver. 

Pretty simple, Michael. I’m afraid your research is mistaken.

Heat treatment to harden silver requires an alloy, generally of
silver with copper, such as sterling silver, in which the two or more
alloying metals are not completely soluable in each other at room, or
other lower than annealing temperatures. Copper is fully soluable in
silver when they are molten, but increasingly less so once solid, and
as the temperature gets lower. (Look at a silver/copper phase diagram
and you’ll see a zone at each end that shows the percentage of copper
than can be held in stable solution in silver, or vice versa, at a
given temperaqture)

Sterling silver can be hardened by heating (and yes, 600-650F is the
correct temperature range) because at these temperatures, although
the structure does not fully recrystalize (anneal) the copper is
able to come out of solid solution in the silver crystals, migrate to
and recrystalize along the grain boundaries between the silver rich
crystals. This makes the grain boundaries much less able to stretch
and deform when the silver crystals themselves are deformed, thus
making the whole mass much harder and stiffer. Even very slow cooling
after annealing will do some of this, and this is why quenching
sterling silver from above about 750F after annealing, makes the
silver softer than if allowed to fully air cool.

This effect, called precipitation or age hardening, does not occur
with fine silver, because there is no structural change that can
occur from simple heating (to any temperature) that will make
crystals or the boundaries between them, less deformable. Annealing
fine silver at a higher temperature or for extended periods of time
will cause grain growth, which will reduce the metals strength,
malleability, ductility, etc, but that just makes it easier to break
or tear. It does not increase the hardness at all. The ONLY way to
harden fine silver is cold working, such as rolling, hammering,
twisting, or the like, in ways which deform and stress the crystal
structure. There is simply no heat treatment that can do it to truely
fine silver.

There MAY, however, be so-called “micro alloys” of silver, where the
silver is alloyed with tiny percentages of odd materials (such as
calcium, among other elements, in one micro alloy example I’m aware
of), which MIGHT be able to be heat treated. But I’m not sure off
hand if this is the case. I’m aware of such alloys marketed because
they can, due to the tiny percentage of alloy, still legally be
marked as “fine”, or .995 pure, but are still harder and more
durable than actual pure silver. What I don’t know is whether such
alloys offer heat treatments to increase hardness. It seems
reasonable to think such a thing might be possible, and it would be
worth asking your refiner or metals supplier if they know of such
alloys. No doubt some other kind Orchidian can suggest a supplier.
I’ve got a bit of the micro alloys in both silver and gold, and
they’re nicely similar in color, etc, to normal pure metals, only
harder (the silver works much like sterling for hardness, while the
gold works much like 18K, yet both are almost pure) However, I
don’t, right off hand, have the name of the supplier in my head… If
you wish, email me and I’ll try to see if I can look it up.

Hope that’s of use.
Peter Rowe

600-650 degrees Farenheit (almost 350deg C) is the temperature at

which fine silver anneals. So what happened was predictable.

    Not to me. My research suggested that 600F was the correct
temperature to achieve full hardness in fine silver. Obviously my
research was badly mistaken. 

I would be very interested in where you found that Do
you have the source? I didn’t think fine sil actually heat hardens at
all. Sterling, yes. Perhaps when they wrote ‘silver’ they meant
sterling.

I admit that it’s not commonly known 999sil anneals at a relatively
low temp:

“… The heat generated in cold working may be sufficient to cause
silver to partially anneal…”

    I already know that the silver has been annealed; what would be
really helpful is if somebody could offer the correct procedure for
hardening fine silver. 

Do you mean hardening fine silver in braided form? I’ll assume so. A
certain amount of experimentation might be in order here. I can’t see
what you could do to harden braided wire apart from gently and
repeatedly bending portions of the bracelet back and forth in an
attept to work harden it and gradually make your way around the whole
piece. You risk distorting the look of it, but then work hardening is
most effective when the metal’s distorted in some way.

In a case like this where the bracelet is not viable in annealed
silver it’s often better to start the piece again, using silver at
the correct work hardened state. The end product will probably be
superior knowing now what you do about the metal’s properties.

For applying balls to the ends of the wire I’d suggest a cold join
method such as crimping.

For the next piece: to get the silver wire partially hardened try
drawing it down from a certain larger dimension (say 3x the desired
gauge) without annealing and so work harden it by the time you’ve
drawn it down. When you know what degree of hardness you want in the
wire either make it all yourself from bought wire of that heavier
gauge, or instruct your supplier to start from A and continue drawing
it down to B without annealing between.

Brian
B r i a n A d a m
e y e g l a s s e s j e w e l l e r y
Auckland NEW ZEALAND
www.adam.co.nz

To my knowledge you only can heat tread an alloy, like sterling
silver not fine silver.

Vince LaRochelle, Oakridge, OR

I don’t do a lot of silver, but I’ve done a good amount of heat
treating with gold, heat treatable platinum and soon with argentium
sterling. As far as I remember you can’t acheive heat hardening on
fine silver. (I’m sure Brehpol has something to say about it, but
I’ve lent my copy out and can’t look it up right now) It’s the
copper in the sterling alloy that allows the metal to harden. You
definately can’t use any formula for heat hardening sterling on
fine silver. The metal just doesn’t react in the same manner.

If this is the case I’m afraid the bracelets are ruined and there’s
nothing short or melting them down and redoing them that will help.

Larry

I already know that the silver has been annealed; what would be
really helpful is if somebody could offer the correct procedure
for hardening fine silver. 

I’m fairly sure you can’t heat harden pure metals, only alloys. If I
am correct, you cannot fix your mistake with heat-- that’s why I
suggested tumbling to try to re-harden your fine silver.

–Noel

Why don’t you make a flat cuff, or wire framework bracelet and
attached your woven pieces to it mechanically. Might not be the
bracelet you were aiming for, but you won’t have to trash the work
you’ve already done.

Steve Brixner
www.brixnerdesign.net

To everyone who has responded, thank you. I have indeed read about
’age hardening’ in alloys, and understand it to some degree. This
is one reason I haven’t had high hopes for the fine silver, which
suddenly doesn’t seem quite as much of a pleasure to work with
anymore. I’ll try giving the pieces a good long tumbling and see if
that helps. If not, I’ve been A: trying to think of ways to use the
soft braids (this stuff is as soft or softer than the junk base
metal they sell at teen fashion shops (for more money than I’d sell
the fine silver bracelets for)) and B: thinking about mashing the
melted scrap into some sort of coin pendants.

The source of incorrect was the Rio Grande 2004-2005
Gems & Findings catalogue, page 44. Fine silver was mentioned only
briefly, but was clearly included as a material which could be fully
hardened with a 1/2-1 hour soak at 600F.

    To everyone who has responded, thank you.  

Thanks for your response.

Also thanks for disclosing your info source (I hope someone from Rio
will take note) however I’m sure you really ought to have verified
that by cross referencing it with other sources. One
source is often not enough. People - and large institutes - are
sometimes fallible. If you’d looked around a little more you’d very
likely have discovered the error yourself and saved yourself a
bracelet fix-up job.

Don’t give up on fine silver. Try my suggestion mentioned earlier in
this thread for pre-work-hardening the wire before you start
braiding.

Brian
B r i a n A d a m
e y e g l a s s e s j e w e l l e r y
Auckland NEW ZEALAND
www.adam.co.nz

           The source of incorrect was the Rio Grande
2004-2005 Gems & Findings catalogue, page 44. Fine silver was
mentioned only briefly, but was clearly included as a material
which could be fully hardened with a 1/2-1 hour soak at 600F.

They goofed on this one, it looks like a mixture of stress reliving
and annealing The sterling will age harden to some minor
degree at 600F but not much unless it has been solution treated just
prior to ageing and yellow karat golds with enough copper in their
alloy will age harden at that temperature. The rest of the listed
metals will not. They also omitted the solution treatment part of the
process for age hardening sterling on page 39 in the same catalog.

Jim Binnion
James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau

     The source of incorrect was the Rio Grande
2004-2005 Gems & Findings catalogue, page 44.  Fine silver was
mentioned only briefly, but was clearly included as a material
which could be fully hardened with a 1/2-1 hour soak at 600F. 

Hi Michael,

I apologize for this error in the Rio Grande catalog. I should have
caught it before it was published. I am in the process of reviewing
all of our annealing and age-hardening tips, and will correct this
one. Sadly I’m past the point where I can fix it for the next
catalog. If you want to discuss this, I invite you to contact me
directly.

Kevin Whitmore
Raw Materials Manager
Rio Grande
7500 Bluewater Road NW
Albuquerque, NM 87121
USA
(505) 839-3114 (voice)
(505) 839-3135 (fax)
@Kevin_Whitmore

I’m not sure why everyone seems to be jumping on the “the bracelets
are ruined” bandwagon.

No, you can’t heat-harden fine silver. No, fine silver will NEVER
be as hardenable as sterling.

BUT, running the bracelets in a tumbler with mixed-shape stainless
steel shot, water, and a drop of dish soap or burnishing compound
for a day or so will harden it and brighten it as much as possible,
with very little (if any) distortion. It’s quite likely that,
depending on the design of the bracelets, the result will be both
durable and wearable.

It is definitely worth the effort, before giving the work up as
lost. There’s nothing to lose.

Karen Goeller
@Karen_Goeller