Electrochemistry Silver Conservation

[Irons2]

Conservation as in preserving old coins and other artifacts.
I'm sure most of us have come across items in our travels that were too nice or valuable to throw into the melting pile, but were a bit corroded or too tarnished to be displayed, well here's how to remedy that situation:

http://nautarch.tamu.edu/CRL/conservationmanual/File13.htm

Don't do this with valuable collectable coins or the value might be affected in a way that will make you cry. :mrgreen:

Since this mostly involves Electrochemistry, I thought this would be a good home for the topic.

 

[Palladium]

Great find and good read Irons. It's now a pdf on my Scribd account.

 

[Irons2]

Great find and good read Irons. It's now a pdf on my Scribd account.

Thank You, Sir.
Lots of good info for PM recovery too, if one know how to apply it. 8)

 

[pesco]

Good find, especially the stabilization and consolidation are quite interesting.

There is an excellent method of conservation which prevents silver objects developing oxide/sulfide layer. Its very thin chrome plating. Few minutes in chrome plating bath and the layer is completely invisible yet thick and strong enough to keep the silver object shiny for years even if it is in constant use. It might however affect the item value in some cases. Last time I've done it 15+ years ago so can't recall details from top of my head, but if someone is interested post reply or PM me.

 

[goldsilverpro]

I would think that chrome plating would always affect the value of a coin, no matter how thin it is. I certainly wouldn't recommend its use.

 

[pesco]

I have been plating silver (plated) stuff like picture frames, jewellery boxes, tableware etc.
Works like a dream.

 

[goldsilverpro]

I have been plating silver (plated) stuff like picture frames, jewellery boxes, tableware etc.
Works like a dream.

I didn't say it didn't work. Here's a quote from a guy in India on finishing.com suggesting the same process. I don't think I would use it on tableware, though.

b.1) This will be electrolytic plating process of depositing a fraction of chromium over the silver. There will be a reduction in the colour of the finish, but it will be insignificant. But a very good protection (would depend on the thickness of Cr). Limitation: Chromium disposal. There might be some reduction in surface conductivity too.

http://www.finishing.com/3800-3999/3946.shtml


On collectible coins, those that have a value exceeding the Ag value, I think it would be a huge mistake to use this process. Collectors expect to see the tarnish and wouldn't like it if they knew the coin were contaminated with Cr. Even on bullion coins, I would pay less for them if I knew there was a Cr layer on them. Similarly, I would pay less for a silver coin that has been Rh or Au plated (unless it were vermeil).

 

[NobleMetalWorks]

Why wouldn't you just plate with Rhodium? I hardly know anything about Rhodium Plating other than most silver jewelry is Rhodium plated now days. My better half works in a jewelry store, she's always complaining about people who just come in to get things Rhodium plated, because it takes her time away from sales. If you really want to preserve something silver so that it keeps that silver look, it seems to me that Rhodium would be the very best choice because of it's durability, hardness and how it looks.

Would this be anymore expensive in terms of equipment, than plating with some other metal? I understand Rhodium is expensive, but considering that it plates at the microscopic level, the cost probably doing really amount to very much at all.

Scott

 

[goldsilverpro]

The problem with Rh is that it looks nothing like silver, which is the whitest metal. Rh really doesn't have the rich beauty of silver. Also, if you ever wanted to remove the Rh, you would have to do it mechanically.

 

[NobleMetalWorks]

The problem with Rh is that it looks nothing like silver, which is the whitest metal. Rh really detracts from the rich beauty of silver. Also, if you ever wanted to remove the Rh, you would have to do it mechanically.

Silver has been my favorite metal for years, you are right about it's luster, I can see your point. If you wear silver jewelry, it doesn't seem to tarnish and I'm guessing it's because of our bodies natural oils. I wonder if there is some way to prevent silver from tarnishing this way? Similar to storing a gun away for a long period of time.

Scott

 

[BAMGOLD]

Not that this has much to do with this thread, but it does in a round about way.

I metal detect and I clean my coins in a version of this
[youtube]http://www.youtube.com/watch?v=dtAkHGbDvmM[/youtube]

 

[pesco]

I have been plating silver (plated) stuff like picture frames, jewellery boxes, tableware etc.
Works like a dream.

I don't think I would use it on tableware, though.

If you thinking of toxicity of chromium then there is very little to worry about. Chromium oxides are REALLY tough and wont go to the meal without a serious fight :mrgreen:
Otherwise all stainless steel kitchenware/tableware would be banned - stainless is stainless because of high content of chromium. Chromium oxides forming on the surface prevents corrosion of SS.

Regards