# Plating on Sterling Silver Flatware



## publius (Mar 30, 2016)

I am processing a batch of sterling silver. It consists of mostly flatware. Some has a gold tone to it and one piece had thin plating that wrinkled like an orange when placed in nitric acid. There was no real residue left on the filter. What could cause the orange peel effect and how should I handle the cemented silver if I wanted to use it as electrolyte in Kadriver's amazing silver cell set-up?

Robert


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## nickvc (Mar 30, 2016)

You said it had a gold tone, now does that mean it looked like gold or that the silver was tarnished?
If the silverware was gold plated the gold can and does migrate over time into the silver unless there is a barrier to arrest the action, usually nickel.
The silver nitrate should be fine to cement but you say you had residue on your filter, try putting it in a beaker add a little HCl and drops of nitric, then test with stannous, this will tell you if you had any good plating.


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## publius (Mar 30, 2016)

Thanks nickvc, Some of the flatware has a gold tone. I have see such before. I really did not have much of anything on the filter paper but I'll try the stanus test. The real concern is the bright silver flatware that had the orange peel form before desolving. I recall that sometimes a thin flash plate of ruthium(?) is plated to protect from the flatware tarnishing. If that is the case the Pt group metals sometime plate over when using the Thrum set up even at 3.4 Volts. That is my concern. If these items are plated with a Pt group, how should I deal with removing them before I make my electrolyte?


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## FrugalRefiner (Mar 30, 2016)

I've not read of silver being plated with ruthenium (although anything is possible), but jewelry is often plated with rhodium. Rhodium is very difficult to dissolve, even in AR. If it's rhodium, it would not dissolve into the electrolyte of a silver cell. It would end up in the slimes.

Dave


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## publius (Mar 30, 2016)

Thank you, Dave. I could not remember which of the Pt daughters is was. I do remember having some spectacular crystal growth in a silver cell that the speculation on this forum was Pb or Rhodium. 

This time I'll convert to AgCl and then use ammonia to ensure no lead gets in before I use the cement for the electrolyte..


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## FrugalRefiner (Mar 30, 2016)

publius said:


> Thank you, Dave. I could not remember which of the Pt daughters is was. I do remember having some spectacular crystal growth in a silver cell that the speculation on this forum was Pb or Rhodium.
> 
> This time I'll convert to AgCl and then use ammonia to ensure no lead gets in before I use the cement for the electrolyte..


Lead is a possibility with flatware, especially if a piece has been repaired with a lead based solder. 

If anything was rhodium plated, the plating will not have dissolved.

If you're concerned with contamination, I'd just cement the solution on copper. The only contaminants at that point would be platinum, palladium, copper, and possibly mercury, though that's unlikely. None should cause any problems when you redissolve the cement to make your electrolyte. Lead will not cement on copper, so if it was present it will be left in solution when you cement.

Dave


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## publius (Mar 30, 2016)

Oh! Great, Dave, now I have to worry about Hg!
LOL 
That is why I was going to go the AgCl NH3 route.


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## solar_plasma (Mar 31, 2016)

Just for the record, Hg _might _be a contaminant _if_ parts of the scrap were fire gilded, a method that was used until about 1945. Gold amalgam was brushed onto copper and then the Hg had been vaporized. I found texts about museum restoration of fire gilded that stated the Hg would not be removed completely under this process.

I don't know, if silver could be fire gilded, too.


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## nickvc (Mar 31, 2016)

There is one other possibility, I have come across sterling that is fine silver plated to avoid the tarnish problem, it could well be the mystery here, most I came across was fairly new, last 20 years, it would also explain why that particular silver looked bright.


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