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Author Topic: Bronze Disease on red copper coins-How to cure  (Read 1830 times)

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Offline Istinpolin

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Bronze Disease on red copper coins-How to cure
« on: August 21, 2006, 05:46:09 pm »
Dear Friends

I have this one coin, which is depicted below, which has some BD on it and it is growing. I mean, usually, I do not mind BD on cheap or common coins. But this coin is very very rare, in fact extremly rare, the condition is really good for Ottoman coins and this coin is very expensive. I am not willing to get eaten up by BD. It has to be cleaned. I know there are many good advice in this section, but I thought that this is red copper and not coated with a patina it may be different. I am very reluctant to touch this coin, but it has to be done. I dont only want to get rid off the BD but only clean this 100%. After all it will be displayed for a couple of months in London. Hopefully a year long.

So what do you suggest? When you explain to me what to do please eyplain it to me like you would to a complete moron.

Please also follow the history section if you are interested in this coin.

Best wishes,
Burak

Offline Arminius

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Re: Bronze Disease on red copper coins-How to cure
« Reply #1 on: August 22, 2006, 07:55:07 pm »
I use 3 methods (sometimes in combination):
- try to remove the loose green dust mechanically (but use soft tools)

stabilise the coin by soaking with / soaking bath in:
- alkaline weapons oil (needs a dry coin) eg.: Ballistol
- diluted soda solution (some hours, heating sometimes improves the desired result)

A.

Offline Jerome Holderman

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Re: Bronze Disease on red copper coins-How to cure
« Reply #2 on: August 23, 2006, 08:02:08 pm »
Are you 100% certain that it is Bronze disease and that it is growing? Based on the pictures I would not have thought that it was bronze disease at all, only some spots of green patina. It just does not have the ....Fuzzy... look that BD usually has and the color looks different. Is it soft and powdery when scraped with a needle or other small instrument?

Retrospectator

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Re: Bronze Disease on red copper coins-How to cure
« Reply #3 on: August 24, 2006, 05:51:16 am »
Are you 100% certain that it is Bronze disease and that it is growing? Based on the pictures I would not have thought that it was bronze disease at all, only some spots of green patina. It just does not have the ....Fuzzy... look that BD usually has and the color looks different. Is it soft and powdery when scraped with a needle or other small instrument?

I must admit these were my first thoughts too when I saw the picture.

Offline Istinpolin

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Re: Bronze Disease on red copper coins-How to cure
« Reply #4 on: August 24, 2006, 06:00:53 am »
Hi

I am not sure what it is. I thought since it is green there was reason for a BD alarm.
I dont think that this is BD as well now. It is softer. How can I remove it.

Burak

Offline Jerome Holderman

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Re: Bronze Disease on red copper coins-How to cure
« Reply #5 on: August 24, 2006, 06:21:41 am »
Personally I would not attrmpt to remove it on a very Rare coin. If it was a common LRBC I would take a diamond dusted pick and gently scrape at it minimize it, but the risk of scratching the coin and making things worse is to high for me to try that on something of substantial value...

Retrospectator

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Re: Bronze Disease on red copper coins-How to cure
« Reply #6 on: August 24, 2006, 06:52:31 am »
Hi

I am not sure what it is. I thought since it is green there was reason for a BD alarm.

Burak

BD or not BD? That is the question. ;)

When it comes to describing BD symptoms, and how the powdery substance can be removed, I don't even really like to apply the word 'scrape'. It conjures up pictures in my mind of coins with apparently suspect yet harmless patinas getting excavated and made less attractive because their owners are convinced that it has BD! :laugh: Powder debris from harmless patina can also result if one 'scrapes' hard enough. For this reason I prefer to say that the powdery substance can be 'pushed' or 'brushed aside'. :) 

Offline moonmoth

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Re: Bronze Disease on red copper coins-How to cure
« Reply #7 on: August 24, 2006, 09:19:03 am »
I have a couple of coins which had growing spots of BD.  I brushed them with a brass brush and then simmered them in a sodium carbonate/sodium bicarbonate solution for an hour.  The BD seems to have gone, but there is a nasty hole in the patina which I suppose can't be helped.  here's one.

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