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Topic: Silver stains  (Read 3704 times)

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Offline Urbanium

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Silver stains
« on: June 04, 2018, 12:19:52 PM »
I was doing a silver nitrate solution - metallic copper experiment (growth of reduced silver needles on copper wire) and some black stains remained on the furniture, I guess it's silver or silver oxide.

How could I remove these stains without damaging the furniture? The surface material is something like wood laminate/wood veneer.

Tried with a cloth and detergent, 10% acetic acid, baking soda... but none of these worked.

Offline Borek

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Re: Silver stains
« Reply #1 on: June 04, 2018, 12:26:43 PM »
I am afraid you are in troubles, can't think of a safe way of oxidizing the silver so that it can be removed.
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Offline Arkcon

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Re: Silver stains
« Reply #2 on: June 04, 2018, 02:02:06 PM »
Congratulations.  You now have a lab bench.  This piece of furniture, as Borek: has described, is now permanently stained.  It is a lab bench, and it now has character -- as a lab bench.

If you want it to be something else, like a dining room table or a kitchen table or a coffee table, then you are out of luck, because it is not any of those things anymore.

I actually used an "extra" coffee table as a lab bench as a kid -- staining it with such things as Prussian Blue and other things, and took it to college to use as a coffee table again.  And then I left it behind when I left.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline Urbanium

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Re: Silver stains
« Reply #3 on: June 05, 2018, 04:33:05 PM »
Unfortunately it's not a lab bench, it's in the kitchen and it does not belong to me...

Are you saying there is absolutely nothing I could use to remove these stains??  Thiosulfate, diluted HCl, something else...?

Offline wildfyr

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Re: Silver stains
« Reply #4 on: June 05, 2018, 05:38:14 PM »
Ammonia is the only suggestion I have. It's a long shot.

Offline Arkcon

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Re: Silver stains
« Reply #5 on: June 05, 2018, 09:22:49 PM »
Ammonia is the only suggestion I have. It's a long shot.

I've tired that on cheap Ikea cabinets in a lab to removed silver nitrate stains.  It doesn't work.  And I used 33% reagent ammonia, not household strength.

I've used concentrated nitric.  That does work.  That also ruins the surface, making it porous.   The home user isn't going to get that easily, nor should they.

Unfortunately it's not a lab bench, it's in the kitchen and it does not belong to me...

Are you saying there is absolutely nothing I could use to remove these stains??  Thiosulfate, diluted HCl, something else...?

Concentrated nitric acid, or fire and lots of it.  Wha ... you want the stain gone or not?

Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline wildfyr

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Re: Silver stains
« Reply #6 on: June 05, 2018, 09:49:12 PM »
I know I've used lab grade ammonium hydroxide or ammonium chloride (can't remember which) to get silver chloride (and probably oxide because I let it sit around forever before dealing with it) residue out of glassware. It is very stubborn otherwise, even to nitric acid or piranha, that is why I suggested ammonia for this. Silver likes to make [Ag(NH3)2]+ OH-. Tollens test is based on the formation of this species.

Offline Enthalpy

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Re: Silver stains
« Reply #7 on: June 06, 2018, 12:10:02 PM »
Could the furniture be stripped of all its paint with a sander, then painted and lacquered again?

I actually used an "extra" coffee table as a lab bench as a kid -- staining it with such things as Prussian Blue and other things

So that's why you became a chemist: you made worse stains as a kid than I did.

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