My Argentium Silver experiment

[tom_grace_stokes]

Hello,

I tried a little experiment with my AS. I was trying to harden some
20 gauge wire. I shaped some into earrings and some I just cut at
various lengths to shape afterward. I put them all on a firebrick and
enclosed it into a pyrex container. I heated them in my oven but my
oven only goes to 450 degrees so I heated them for almost 2 hours.
Other than discoloration, there was no perceptible difference in the
temper. I was hoping to get it much harder but my oven probably does
not get hot enough - so my experiment for my goal did not work.
However, Hoover and Strong has told me that they will sell the work
at whatever temper you ask for, meaning, they have to draw it through
a die. I am wondering would that destroy the germanium layer, in
which case you have to then heat it again, destroying the hardening?
It’s like a Catch-22!

Grace

[Trevor_F2]

I tried a little experiment with my AS. ... I put them all on a
firebrick and enclosed it into a pyrex container. I heated them in
my oven but my oven only goes to 450 degrees so I heated them for
almost 2 hours. Other than discoloration, there was no perceptible
difference in the temper. 

Hello Grace,

If I were you I’d try the same, more or less, again but skip the
firebrick. I strongly suspect it would never build up to the
specified temperature --it is, after all, a firebrick-- and
consequently would act as a cooling element in your procedure. It is
my understanding that 450 F should be sufficient to achieve the
precip hardening effect.

Another thing to keep in mind is that the precip hardening works best
if you anneal your Argentium Sterling (AS) before it goes into the
oven. As I’ve reported elsewhere this can significantly improve the
degree of hardness achieved.

Cheers,
Trevor F.
in The City of Light
www.touchmetal.com

[judymw]

Hello Orchidland,

Grace posted about her attempt to harden Argentium silver in her
oven, which only goes to 450 degrees F. I’m thinking, what about
self-cleaning ovens? What if the metal was run through a cleaning
cycle? My electric oven heats to about 800 degrees F in cleaning
mode.

Using that much energy to heat up a huge oven is rather wasteful, so
I think I’ll stick with my little programmable kiln. BUT, the next
time I run a cleaning cycle, I think I’ll stick in some Argentium.
Wonder what will happen. Anyone else going to try this?

Judy in Kansas, where the temps are still August-like, but next
weekend is supposed to bring relief.

[Cynthia_Eid]

Hi Grace,

Try another experiment: Heat the Argentium Sterling Silver in your
oven for four hours (heating the silver longer does not have a
negative effect). Do not enclose it. Either put it in an open pyrex
dish, OR put it on a firebrick.

If four hours works, you can experiment to see if 3 hours is enough
at your oven’s temperature. If four hours does not work, try 5 or 6
hours. I am pretty sure that 450 is hot enough to do the
precipitation hardening.

If you order the wire hard, soldering will anneal it.

If you do not need to anneal it or solder it, you can ensure the
protective germanium oxide layer by heating the metal at 250 degrees
F for 10-20 minutes (or longer. Longer will not change the temper. It
might create a bit of discoloration that can be removed with pickle
and/or Goddard’s Long Shine Silver Cloth or Liquid.)

Cynthia Eid
http://www.cynthiaeid.com

[richard_hart2]

a firebrick-- and consequently would act as a cooling element 

A firebrick can withstand high heat, but it is not a cooling element
(?). It will get to the same temperature as anything else you put in
an oven The mass of an object determines the time it takes.

Richard Hart

[jbin1]

    If I were you I'd try the same, more or less, again but skip
the firebrick. I strongly suspect it would never build up to the
specified temperature --it is, after all, a firebrick-- and
consequently would act as a cooling element in your procedure. 

Actually the thermal conductivity of the fire brick is very low so
it would heat up on the outside fairly rapidly to the ambient temp
in the oven. The interior of the firebrick would be cooler than the
exterior surface of the brick until the brick reaches equilibrium
with the oven. The exterior surface of the brick will not be
noticeably cooler than the rest of the oven after a fairly brief
time if you are putting it into a pre heated oven. However if you
are putting it into a cold oven the surface temperature of the
brick will track the oven temperature fairly closely.

[Trevor_F2]

If I were you I’d try the same, more or less, again but skip the
firebrick. I strongly suspect it would never build up to the
specified temperature --it is, after all, a firebrick-- and
consequently would act as a cooling element in your procedure.

Actually the thermal conductivity of the fire brick is very low so
it would heat up on the outside fairly rapidly to the ambient temp
in the oven. ... The exterior surface of the brick will not be
noticeably cooler than the rest of the oven after a fairly brief
time .... 

Hello James, et al,

Ok, ok, so I guess I didn’t earn my Mr. Science badge on that one,
fair enough.

What I was driving at, and still recommend, is eliminating the
variables. The temps being talked about are supposed to precip
harden Argentium Sterling (AS), particularly if it has been annealed
first, so if it’s not happening then I’d start removing the unknowns
until you’re either getting the expected results or have demonstrated
that even the simplest set-up fails.

Cheers,
Trevor F.
in The City of Light
www.touchmetal.com

[tom_grace_stokes]

Thanks Cynthia, I will try heating it longer. Do you also suggest
annealing it first before trying to harden it? I would like to skip
that step if possible.

Grace

[Cynthia_Eid]

    Thanks Cynthia, I will try heating it longer. Do you also
suggest annealing it first before trying to harden it? I would like
to skip that step if possible. 

Hi Grace,

It is not necessary to anneal before heat hardening. I don’t do it,
either. (it is necessary to anneal and quench for maximum hardness,
but I am satisfied with pretty darn hard, myself. I think that you
just need to experiment with finding out how long it takes in your
oven. Remember, too, that it may not actually even go to
450F----that’s what the know on the stove says, but we all know that
these things are not super-accurate. I am SURE that you can harden
the Argentium at the lower temperature. It just takes longer, and
enclosing it in Pyrex, which is not very conductive, is not helpful,
in my opinion. Leave the top off.

It can be difficult to measure hardness when comparing, hours later.
Be sure to have a piece of metal that you have not put into the oven
to compare with the heat-treated silver.

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

[Noel_Yovovich]

I’m coming in late, here (been up to my eyeballs in alligators, now
have three hundred Orchid emails) but it occurs to me that the
argentium experiment might have gone wrong because the metal was
"enclosed in a pyrex container". If the lid was close fitting, this
would severely limit the amount of oxygen available to the metal,
thus defeating the purpose, no?

Maybe try it again, annealing first, with no lid.

HTH,

–Noel

[Trevor_F2]

... it occurs to me that the argentium experiment might have gone
wrong because the metal was "enclosed in a pyrex container". If the
lid was close fitting, this would severely limit the amount of
oxygen available to the metal, thus defeating the purpose, no? 

Hello Noel,

Good point. I must confess that I was the person who suggested the
"close fitting lid" business. The idea was that it would be a means
to isolate the Argentium Silver (AS) being heated from any gunk in the
oven that might cause discoloration during the bake. I have tested
this --the “enclosed” bit, not the “gunk” bit-- and it worked fine for
me though it was a small piece of AS in a relatively large pyrex
container.

That said I’ve heard a couple of objections to the closed container
idea and see no compelling reason for actually doing it so perhaps it
would be best to do as you, and Cynthia before you, have already
suggested: use the dish, forget the lid. I think it’s safe to
conclude that I was trying to solve a problem that probably doesn’t
exist.

Cheers,
Trevor F.
in The City of Light
www.touchmetal.com

[Cynthia_Eid]

I'm coming in late, here (been up to my eyeballs in alligators,
now have three hundred Orchid emails) but it occurs to me that the
argentium experiment might have gone wrong because the metal was
"enclosed in a pyrex container". If the lid was close fitting,
this would severely limit the amount of oxygen available to the
metal, thus defeating the purpose, no? 

My gosh, Noel----you are brilliant! Of course! I had focused on
the insulation factor, but that probably is not as significant as
the oxygen factor. Folks were hoping not to have any ill effects
from their dirty ovens by enclosing in pyrex. In fact, though, any
discoloration generally comes off in pickle. The exception may be
the exceptionally dirty oven that is dirty enough that it
smokes…but in that case, it really is time to clean anyways,
don’t you think?

Another interesting thing is that following my suggestion of leaving
the lid off to cut down on the insulation factor also allows the
oxygen in. So, folks, let’s forget the enclosed container idea, ok?

Thanks so much for pointing out what we all should have seen----hind
sight is an amazing thing, isn’t it?

By the way, I am about to send my laptop off for repair, and then
off to Haystack for two weeks, so I don’t know whether I’ll be
available much between now and September. So, remember
info@argentiumsilver.com as a resource…(as well as Trevor and all
the other brilliant minds on Orchid.)

Cynthia Eid
http://www.cynthiaeid.com