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Work hardening Argentium without a tumbler


#1

I am wondering if anyone knows how I could work harden simple
argentium fused wire links and easily clean them in a group setting
with out the use of a tumbler. Unfortunately I need to do it quickly
and easily with beginners

Thanks!


#2

Hi Tina,

I am wondering if anyone knows how I could work harden simple
argentium fused wire links and easily clean them in a group
setting with out the use of a tumbler. Unfortunately I need to do
it quickly and easily with beginners

How about hardening them in a toaster oven*, and then brightening
them up with a steel or wire brush and soapy water?

*AS hardens in 45 minutes at 580 degrees F, or two hours at 350F.
For temperatures in between, adjust accordingly. Since the time does
not start until the metal reaches the temperature, and there is no
negative reaction to extra time in the oven, I usually put my AS in
an open Pyrex dish at the top temp. of my oven for two hours.

Cynthia Eid
http://www.cynthiaeid.com


#3
and there is no negative reaction to extra time in the oven, I
usually put my AS in an open Pyrex dish at the top temp. of my oven
for two hours. 

Leaving an item at aging temperature too long results in a decrease
in hardness from the peak attainable hardness from age hardening.
This is called over aging and can happen to any precipitation
hardenable alloy not just Argentium.

James Binnion
James Binnion Metal Arts


#4
I am wondering if anyone knows how I could work harden simple
argentium fused wire links and easily clean them in a group
setting with out the use of a tumbler. Unfortunately I need to do
it quickly and easily with beginners 

Tina - you ask two questions and the answer to the first is easy -
go to argentium.com and you will find detailed on
hardening Argentium. It doesn’t have to be work hardened but rather
is done with heat.

The second question depends on the nature of the links. If they
produce a chain, and you don’t want to tumble, you are left with hand
finishing. Using a buffer for chains is dangerous and certainly
nothing you want to introduce to a beginner.

If these are chains, you could approximate a finish with a well
polished planishing hammer on a very smooth anvil or bench block.
Then have the students hang the chain from a nail and use fairly
fine - 400 grit - wet or dry sandpaper pulled over the chain. Check
for scratches, if necessary, repeat with finer paper. Then charge a
firm cloth with white diamond Tripoli, and pull it down the chain,
follow with rouge. Have the students reverse the chain, hanging it
from the other end, at each step. These steps will yield a chain that
is slightly more finished, but IMHO, probably not acceptable.

Better solution - get a tumbler.

Judy Hoch


#5

Hello Cynthia,

Your instructions for hardening AS in a toaster oven left me with a
question. I recall that AS should be annealed before being hardened
this way. Does the process of soldering provide adequate annealing,
as it would with standard sterling?

TIA,
Judy in Kansas, where last night temps were sub-zero, but the winds
have died down… Thank goodness!


#6
Leaving an item at aging temperature too long results in a
decrease in hardness from the peak attainable hardness from age
hardening. This is called over aging and can happen to any
precipitation hardenable alloy not just Argentium. 

While Jim may be technically correct the question is, how long is
too long? I have heat treated Argentium Silver for twice our
recommended precipitation hardening times and the hardness test show
no significant change compared with our recommended times.

Further details can be found at argentiumsilver.com

Peter Johns
Argentium International Ltd.


#7

It is technically correct that leaving an item at aging temperature
too long results in a decrease in hardness from the peak attainable
hardness from age hardening. In practice, however, I find no
discernable difference if I leave the silver in an extra 30-60
minutes to be sure that the material reached the correct temperature
for the minimum time. Also, when people use kitchen appliances, which
is typical for Orchid users, they are using temperatures lower than
the maximum of 580 degrees F----at these lower temperatures, there is
less grain enlargement.

What I am reminded from this discussion is how important it is to be
as explicit as possible when giving instructions. I did not intend
that anyone should leave it in the oven overnight, or for an extra 10
hours, yet, I see that my statement implied that it was okay to do
so. I will emend my instructions accordingly.

While I am emending, let me add that if I want a piece made in
Argentium Silver to be as hard as possible, I harden in the oven, and
then tumble, too. I had not mentioned this in the original post, as
the original question had been how to harden and finish Argentium
Silver fused links with low-tech equipment.

Cynthia
Www.cynthiaeid.com


#8

“Over aging” metal (?)

Mr Binnion

i never heard of "over ageing"with heat hardening metal. with all
due respect do you have any hard (little pun)data on your comment?
since i and lots of others heat harden ag sterling it would be of
help to provide some more details.

i can see if temp exceeded in degrees substantially could result in
an annealing effect, but time (?)

zev

ps how zev heat hardens ag silver i use an old cast iron deep pan
with some crumpled aluminum foil on bottom(to keep silver and
thermometer of direct contact with pan). then with oven thermometer
along with ag silver work i cover pan. first on fairly low temp
setting and check till proper temperature is arrived. (careful, pan
gets very hot) i was able to gauge proper dial setting after few
tries. i get higher temp than toaster oven and much less elect usage
that heating up entire oven. should also work with gas stove one
caveat, i use coil type elect stove.flat top may be a problem due to
possible excess heat build up


#9

Hi Judy,

Your instructions for hardening AS in a toaster oven left me with
a question. I recall that AS should be annealed before being
hardened this way. Does the process of soldering provide adequate
annealing, as it would with standard sterling? 

My answer is that yes, silver soldering (technically silver brazing)
anneals Argentium Sterling Silver as well as traditional sterling.

I will also say that for absolutely optimal
scientifically-measurable results, the metal should be annealed
before hardening----however, in my everyday practice, I don’t worry
about whether the AS is annealed or not. The difference in hardness
is minute from my point of view.

Cynthia, outside Boston, where it was so cold and windy today that
my dog, husband, and I all agreed to cut the afternoon walk short!

http://www.cynthiaeid.com


#10
i never heard of "over ageing" with heat hardening metal. with all
due respect do you have any hard (little pun)data on your comment?
since i and lots of others heat harden ag sterling it would be of
help to provide some more details. 

Plenty of data and it is the correct terminology.

James Binnion
James Binnion Metal Arts


#11
While Jim may be technically correct the question is, how long is
too long? I have heat treated Argentium Silver for twice our
recommended precipitation hardening times and the hardness test
show no significant change compared with our recommended times. 

Sorry Peter, the statement was “there is no negative reaction to
extra time in the oven” which you admit is wrong, no qualifications
were given in the statement.

And what happens if your temperature is a little off as well, say a
little too high and then the over aging happens faster. I know you
want it to be simple and easy for people to use your product but
precipitation hardening is a process that requires precision to get
optimum results and the further you deviate from the correct
temperatures and times the less reliable the results. Diffusion (the
mechanism for age hardening) has a logarithmic relationship with
temperature. Since the recommendations constantly given for age
hardening Argentium are using a very imprecise heat sources (oven,
toaster oven, etc) the potential for not getting optimum results are
even greater. So I can easily believe you would see little change
with a doubling of time in the precisely controlled temperature of a
laboratory kiln at your facility I am not so certain of those
results in a home oven.

Regards,

Jim

James Binnion
James Binnion Metal Arts


#12

Get a tumbler. But get a vibratory tumbler. Use steel shot and
burnishing liquid which dilutes and lasts forever. Your Argentium
chains will be beautiful in about 10 minutes. Great for classes. Safe
and instant gratification on items they can take home right away.

Pat Klein
Pat Klein Designs


#13

mr binnion

in article you refer too it states that “diffusion” (the process is
related to the hardening) is “exponentially related to temperature"
i don’t see where the relationship to “time” has such an
"exponential” effect. as far as data of over ageing, due to “time” in
any practical manner where will i find that?

zev


#14
Get a tumbler. But get a vibratory tumbler. Use steel shot and
burnishing liquid which dilutes and lasts forever. Your Argentium
chains will be beautiful in about 10 minutes. Great for classes.
Safe and instant gratification on items they can take home right
away. 

Pat - I have to disagree. If you are going to use steel, get a rotary
tumbler and stainless steel shot, mixed shapes. You are correct to
use diluted burnishing liquid. The smallest vibratory tumbler that is
rated for steel is the 6 liter, AV25SS, and it costs about $500. The
real cost is steel for the machine - it uses 50 pounds of steel at 12
to 15 dollars per pound. A small rotary and 5 pounds of steel will do
the job in 30 minutes. Using an unrated machine for shot will result
in early machine failure. To run a vibratory machine with
insufficient shot results in no real finishing at all. I’ve actually
seen little roads on the surface from the shot jiggling in place,
rather than turning properly.

Incidently, steel shot runs for the same length of time in either a
rotary or vibratory machine. 10 minutes isn’t long enough in either
one.

Judy Hoch


#15
in article you refer too it states that "diffusion" (the process
is related to the hardening) is "exponentially related to
temperature" i don't see where the relationship to "time" has such
an "exponential" effect. as far as data of over ageing, due to
"time" in any practical manner where will i find that? 

I did not say time was a exponential variable however diffusion is a
time driven process. “Diffusion is a time-dependent process,
constituted by random motion of given entities and causing the
statistical distribution of these entities to spread in space.”

Diffusion is governed by time, temperature and several other
variables.

For a good reference to age hardening in precious metals get Mark
Grimwade’s “Introduction to Precious Metals”

For a good presentation on age hardening with a chart showing over
aging effects on hardness VS time (slide 15) see

this is a web presentation of a PowerPoint slide show, you can also
download the.ppt file if you desire.

for more on diffusion on the web see Fick’s law of Diffusion

Atomic Diffusion

Jim

James Binnion
James Binnion Metal Arts


#16
The smallest vibratory tumbler that is rated for steel is the 6
liter 

Yikes! I have a little bitty vibratory tumbler I bought used, and it
came with a little steel shot (though I acknowledge I have not found
it very effective used this way). The chamber is quite small, maybe
3" or 4" on a side, so there’s not a lot of room in there. What, if
anything, is this good for? Ceramic media?

I have your book, Judy, and read it twice, but it doesn’t seem to
stick in my head-- and it’s SO much easier to ask you than to look
for the answer in the book! I think I need a workshop on using
tumblers-- I am, as they say, a visual learner.

Noel