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 Replies: 26 / Views: 2,856 |
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Pillar of the Community
United Kingdom
2838 Posts |
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Pillar of the Community
United States
2596 Posts |
I couldn't tell you, if its not harming the coin I guess "we'll" just have to wait and see how it turns out. Hope it will turns out good.  Looks like you have some nice coins in that bowl. Is that a provincial its leaning on? |
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Pillar of the Community
 United Kingdom
2838 Posts |
Quote:
Is that a provincial its leaning on? Yep - its a year 5 Philip from Viminacium  |
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Bedrock of the Community
United States
10045 Posts |
Wow...that's interesting, I've never seen such a thing.  Is the coin bronze? It appears to be leaching out something. I would soak that coin by itself, so it doesn't contaminate others. |
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Moderator
 United States
23731 Posts |
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Pillar of the Community
United Kingdom
2838 Posts |
I too have never seen anything like it. The coin is bronze - this is it before soaking, it looked clean and was not covered in anything:  I think your right, I've removed it to its own pot and its soaking to see if it happens for a third time. I had thought it was salts originally but don't believe that any more. |
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Pillar of the Community
United States
4778 Posts |
Interesting. I got to watch out for this (or anything else that looks questionable) when I start cleaning ancients (hopefully in the near future).
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Pillar of the Community
United States
2044 Posts |
This may seem unlikely but what if the coin has lead mixed in with the copper?
I have seen ancient lead coins look white.
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Bedrock of the Community
United States
10045 Posts |
I'm no chemist, but it's fun to guess what happened here. If there was "white lead" in the coin. It's pretty stable; I think you would see it before the soak. I've seen waxes turn white in water, such as water spots on a coffee table. Perhaps the coin was waxed? |
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Moderator
Australia
16868 Posts |
To react that fast in just distilled water, it can't be anything naturally residing on a coin that's already been partially cleaned. I suspect it's some kind of coating or perhaps artificial patination that's coming off.
What's the little white ring near the rim at 5 o'clock? It's looking suspiciously like a filled hole to me.
From the "before" pic, it looked clean enough - what made you decide to soak it?
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Valued Member
United States
313 Posts |
My guess Chemical reaction with the other coins and the water? |
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Pillar of the Community
United States
1315 Posts |
My guess would have to be a very old coating of wax that you didn't notice before soaking.
Take a little of it and put it on a glass surface and let it dry. It might help to determine if it a waxy substance or something else like a varnish or a metallic substance.
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Bedrock of the Community
Australia
21788 Posts |
I suspect that the coin has some kind of organic partly water soluble coating on it. The water seems to have softened and expanded it. Does the coin have a slimy feel when wet?
That little white ring that Sap spotted suggests to me that the coin may have been laquered, perhaps as a method of preserving it. I have sprayed acryllic laquer on a coin myself by way of experimentation.
Try soaking it in kerosene, then methylated spirits, then acetone, then let it dry naturally.
All of the abovementioned are organic solvents, but the methylated spirits has a hydroxide radical (OH)-, which is the same as water when it splits into a H+ and an (OH)- radical, which explains why water is a good solvent for so many things.
The other two are purely organic solvents. The high volatility of the acetone will eliminate the need to dry it. So will the methylated spirits.
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Rest in Peace
United States
9104 Posts |
Could it be like the electrolysis caused by dissimilar metals in contact?
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Bedrock of the Community
Australia
21788 Posts |
biggfredd: I don't think so. bobbbyhelmet has not reported any loss of metal from the coin.
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Rest in Peace
United States
9104 Posts |
For the right side up folks, methylated spirits = denatured alkyhaul, commonly 90% ethanol and 10% methanol.
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Replies: 26 / Views: 2,856 |
Posted 01/23/2012 11:10 am
