Conserving modern bronze coin
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5 posts in this topic

rshalgi   
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I've purchased this error coin that sadly has some verdigris.  The composition, according to numismatic references, is 97% copper, 2.5% zinc, and 0.5% tin.

I wonder if professional conservation by NCS would improve the coin or harm it. I tried posting this question on the "Ask NCS" forum here, but it's been 7 days and my question was not approved yet, so I don't know if that forum is still active or not. I know that there are no absolute guarantees when it comes to conservation and that there are always risks, but I'm looking for opinions from people who tried similar things in the past.  

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jcriller   
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good day, i have forwarded numerous coins to ncs with some good results, in some cases the grade stayed the same but the coin looked much better. I am no expert on the above coin but NCS will definately get the grit off, the only problem i see is that at the bottom picture on the right hand side of the coin seems to be some damage (the green spot). you might get a details grade. 

The response time you get from NCS is quite shocking, i have posted questions before and it takes weeks to get answered.

 

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Star City Homer   
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Quote

The response time you get from NCS is quite shocking, i have posted questions before and it takes weeks to get answered.

 

And even longer to get stuff back from NCS...okay just kidding.  Actually I've posted a question there, and in the interim while waiting for a response, the items have been sent, conserved, graded and sitting around my house now for months.  

Even though it's a lengthy process at least they are not rushing things.  I've sent various items (medals/coins) with similar age/problems/metals--can't say they were exactly the same, but similar.  I have been invariably happy.  I'm not worrying about grades but surface stabilization for the most part.  NCS will not do something if they don't think it will help.  That said, there is always a risk.  

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JKK   
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I know what I'd do. I'd blow the corrosion off with a mix of borax and washing soda solution, then seal it with a particular kind of wax. I did that on an ancient bronze of Magnentius and it took a while due to the large amount of bronze disease, but the coin was worth saving and I'm glad I did.

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Conder101   
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What do you mean by "blow the corrosion off"?  Are you soaking it in this solution?  Doe it reduce the corrosion or dissolve it?  What does it do tot he color or patina of the coin?

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