Classical Numismatics Discussion
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FORVM`s Classical Numismatics Discussion Board  |  Numismatic and History Discussions  |  Coin Photography, Conservation and Storage  |  Topic: Sicily Punic coin with BD? 0 Members and 1 Guest are viewing this topic. « previous next »
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Author Topic: Sicily Punic coin with BD?  (Read 598 times)
Meepzorp
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« on: December 08, 2018, 04:06:58 pm »

Hi folks,

I have a Sicily Punic coin that I suspect has bronze disease.

It is this coin (scroll down, last coin):

http://www.forumancientcoins.com/meepzorp/gs_sicl_siculo_punic.htm

So far, about 4 or 5 small pieces have broken off of it (the edges) over the years. Where the pieces broke off, there is powdery green residue.

However, if it does have BD, it doesn't appear to be severe - at least, not on the surface. There doesn't appear to be any active corrosion on the surface. The patina doesn't appear to be fake, but it is sometimes difficult to tell.

This coin has a beautiful glossy medium to dark green patina. It would be a shame to ruin it by stripping the patina during treatment.

What does everyone think? Should I leave it alone? Should I treat it immediately? Should I keep an eye on it with the possibility of treating it in the future?

Thank you for your input. Smiley

Meepzorp
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otlichnik
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« Reply #1 on: December 10, 2018, 03:52:09 pm »

Yes, it certainly has BD.

Sadly I would call this leaning towards severe.  To me this appears to be the type where the entire body is susceptible.  It must be a combination of bad alloy - possibly high sulphur content copper - combined with bad environmental situation during its buried life.

The result is that the whole body might be dodgy with a crisp surface clinging stubbornly. 

Can you remove the BD dust with a soft toothbrush without flaking away the surface??

If so, remove as much powder as you safely can. 

I would consider waxing it.  First baking it in the oven at low heat to remove remaining moisture, then, while still warm, applying a thin layer of Renwax.

If you are lucky it will seal out moisture and there will be no self-generating moisture-induced BD under the wax.  Also the wax might help protect the flaking.

Worst case, the BD re-appears under the wax in which case you need to strip it off.

SC
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SC
(Shawn Caza, Ottawa)
Meepzorp
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« Reply #2 on: December 13, 2018, 03:46:16 pm »

Hi otl,

Thank you for the reply and for your advice.

I think I will give that a try in the near future.

As some Forum members know, a few years ago, I treated a few dozen coins for BD by soaking them in sodium sesquicarbonate for several months. Unfortunately, this process usually strips the patina. And it is extremely time-consuming.

This coin has a beautiful patina, and I'd hate to ruin it. Otl's suggestion can be done in one day, and it won't destroy the patina.

Meepzorp
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Meepzorp
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« Reply #3 on: December 15, 2018, 08:22:26 am »

Hi folks,

I treated this coin.

I wrote about it in my "website" thread.

Meepzorp
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otlichnik
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« Reply #4 on: December 16, 2018, 09:51:30 am »

Let us know how it goes and whether the BD comes back.  I think the sandy highlights will come back a bit as the wax dries.

SC
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SC
(Shawn Caza, Ottawa)
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FORVM`s Classical Numismatics Discussion Board  |  Numismatic and History Discussions  |  Coin Photography, Conservation and Storage  |  Topic: Sicily Punic coin with BD? « previous next »
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