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| Attila the Bum |
 Posted: Tue May 10, 2005 5:21 pm |
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I've had something like three dozen
silver or silver plate objects in
storage for several years. They're
all blackened by whatever. Anyone
with a cure for this problem?
Atty (This is my 3116th post to
sci.chem, most of which have
nothing to do with chemistry
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| Uncle Al |
| Posted: Tue May 10, 2005 5:49 pm |
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Attila the Bum wrote:
[quote:2b969f3174]
I've had something like three dozen
silver or silver plate objects in
storage for several years. They're
all blackened by whatever. Anyone
with a cure for this problem?
[/quote:2b969f3174]
Frypan with water fill, aluminum plate or foil (there must always be
water under the aluminum), calgonite or sodium bicarb. Warm the
system and add the tarnished silver. Hydrogen generation on its
surface when it touches aluminum will reduce the tarnish back to
metallic silver. Or use silver polish to erode the tarnish off.
Either way, you want to finish up with a little tolylbenzotriazole (in
the polish). It forms an adherent monomolecular film that prevents
tarnish until it is phsyically breached (e.g, scratched).
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf |
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| muha |
| Posted: Tue May 10, 2005 10:01 pm |
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Your silver was not blackened by whatever - it is volatile sulfurous
compounds doing it. Maybe you are farting too much. |
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| Repeating Rifle |
| Posted: Tue May 10, 2005 11:25 pm |
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in article 42814896.3FC0280A@hate.spam.net, Uncle Al at
UncleAl0@hate.spam.net wrote on 5/10/05 4:49 PM:
[quote:b93a23423a]Attila the Bum wrote:
I've had something like three dozen
silver or silver plate objects in
storage for several years. They're
all blackened by whatever. Anyone
with a cure for this problem?
Frypan with water fill, aluminum plate or foil (there must always be
water under the aluminum), calgonite or sodium bicarb. Warm the
system and add the tarnished silver. Hydrogen generation on its
surface when it touches aluminum will reduce the tarnish back to
metallic silver. Or use silver polish to erode the tarnish off.
Either way, you want to finish up with a little tolylbenzotriazole (in
the polish). It forms an adherent monomolecular film that prevents
tarnish until it is phsyically breached (e.g, scratched).
[/quote:b93a23423a]
The aluminum reduction method certainly works. But be prepared for actual
loss of some silver. A significant fraction of the silver sulfide gets
reduced to a sludge rather than redpositing as polished silver.
Bill |
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| Attila the Bum |
| Posted: Wed May 11, 2005 9:58 am |
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muha wrote:
[quote:112fcedf3d]Your silver was not blackened by whatever - it is volatile sulfurous
compounds doing it. Maybe you are farting too much.
[/quote:112fcedf3d]
That is a possibility, but the
Sci.chem FAQ, Part 7 of 7,
section 31.16 doesn't mention
that possibility.
Have you any empirical results
to share?
Atty (Entrapment? I don't think so  |
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| Aaron Hicks |
| Posted: Wed May 11, 2005 10:13 am |
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Speaking of actual loss of silver...
I have a colleague who plays trumpet; many years ago, I used to do
the same. He brought by several of his instruments, all but one of which
was silver. Of course, they tarnish with use, which he doesn't seem to
mind. In fact, as polishing them removes silver (which eventually requires
that they be re-plated), it's a task that gets put off.
So, I brought out the old standby- "Tarn-X." Great stuff. It
contains, according to the MSDS, thiourea (5-7%), 3-5% sulfamic acid, and
<1% each of a detergent, citric acid, and hydroxyacetic acid. I applied it
to a tiny area with a Q-Tip, as I had never used it on a musical
instrument before.
There was the usual strong sulfur smell, and it instantly came
clean. It's supposed to be a "dip-and-dry" cleaner, and it really does
work that fast, with no effort required. The Q-Tip and the cloth used to
clean the area had no metallic stain, and were not discolored at all.
My concern is whether or not it is chemically removing silver, or
if it's some sort of reduction reaction that is returning silver to its
metallic state- or something else. Anybody know if by doing this, someone
would just end up removing silver?
The email address in the header isn't valid. Send no mail there.
-AJHicks
Chandler, AZ |
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| Marvin |
| Posted: Wed May 11, 2005 10:26 am |
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Repeating Rifle wrote:
[quote:2c77cc90ea]in article 42814896.3FC0280A@hate.spam.net, Uncle Al at
UncleAl0@hate.spam.net wrote on 5/10/05 4:49 PM:
Attila the Bum wrote:
I've had something like three dozen
silver or silver plate objects in
storage for several years. They're
all blackened by whatever. Anyone
with a cure for this problem?
Frypan with water fill, aluminum plate or foil (there must always be
water under the aluminum), calgonite or sodium bicarb. Warm the
system and add the tarnished silver. Hydrogen generation on its
surface when it touches aluminum will reduce the tarnish back to
metallic silver. Or use silver polish to erode the tarnish off.
Either way, you want to finish up with a little tolylbenzotriazole (in
the polish). It forms an adherent monomolecular film that prevents
tarnish until it is phsyically breached (e.g, scratched).
The aluminum reduction method certainly works. But be prepared for actual
loss of some silver. A significant fraction of the silver sulfide gets
reduced to a sludge rather than redpositing as polished silver.
Bill
So will silver polish. My grandmother polished her candlesticks weekly, and eventuially[/quote:2c77cc90ea]
wore through in some places. A silversmith did repairs. |
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| Dirk Bruere at Neopax |
| Posted: Wed May 11, 2005 10:32 am |
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Marvin wrote:
[quote:41825b73d0]Repeating Rifle wrote:
in article 42814896.3FC0280A@hate.spam.net, Uncle Al at
UncleAl0@hate.spam.net wrote on 5/10/05 4:49 PM:
Attila the Bum wrote:
I've had something like three dozen
silver or silver plate objects in
storage for several years. They're
all blackened by whatever. Anyone
with a cure for this problem?
Frypan with water fill, aluminum plate or foil (there must always be
water under the aluminum), calgonite or sodium bicarb. Warm the
system and add the tarnished silver. Hydrogen generation on its
surface when it touches aluminum will reduce the tarnish back to
metallic silver. Or use silver polish to erode the tarnish off.
Either way, you want to finish up with a little tolylbenzotriazole (in
the polish). It forms an adherent monomolecular film that prevents
tarnish until it is phsyically breached (e.g, scratched).
The aluminum reduction method certainly works. But be prepared for actual
loss of some silver. A significant fraction of the silver sulfide gets
reduced to a sludge rather than redpositing as polished silver.
Bill
So will silver polish. My grandmother polished her candlesticks weekly,
and eventuially wore through in some places. A silversmith did repairs.
[/quote:41825b73d0]
Next time get them made in solid silver.
--
Dirk
The Consensus:-
The political party for the new millenium
http://www.theconsensus.org |
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| Attila the Bum |
| Posted: Wed May 11, 2005 10:32 am |
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Hi, AJ. With trumpets, it's the
"lip" that counts.
Why not just mix a bit with AgNO3
and see if you get a ppt? That'd be
a starting point for getting to a con-
clusion, eh?
Atty (I have never aspired to be
an arsonist, but currently
inhabit a town that has a
statue to the critter in it's
harbour |-) |
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| Repeating Rifle |
| Posted: Wed May 11, 2005 2:19 pm |
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in article 1184c66b117c316@corp.supernews.com, Marvin at physchem@cloud9.net
wrote on 5/11/05 9:26 AM:
[quote:e3b8fb1f35]The aluminum reduction method certainly works. But be prepared for actual
loss of some silver. A significant fraction of the silver sulfide gets
reduced to a sludge rather than redpositing as polished silver.
Bill
So will silver polish. My grandmother polished her candlesticks weekly, and
eventuially
wore through in some places. A silversmith did repairs.
[/quote:e3b8fb1f35]
Silver polish WORKS by being abrasive! That is not so obvious using the
aluminum.
Bill |
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