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Author Topic: A question about BD  (Read 1805 times)

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Offline Jiminey

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A question about BD
« on: June 15, 2011, 10:13:05 pm »
This may be a silly question but... was just curious to know if bronze disease can spread to other coins when they are soaking together in DW? Or is it only spread while in the open air?

Thank you

Offline casata137ec

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Re: A question about BD
« Reply #1 on: June 15, 2011, 10:33:25 pm »
I do not know the anser, but I always treat my BD coins seperatly...I figure it is better to be safe than sorry.

Chris
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dupondius

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Re: A question about BD
« Reply #2 on: June 18, 2011, 10:40:16 am »
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Offline benito

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Re: A question about BD
« Reply #3 on: June 18, 2011, 11:49:42 am »
I think that bacteria was  named streptococcus monetarii.

Offline Joe Sermarini

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Re: A question about BD
« Reply #4 on: June 26, 2011, 03:58:00 pm »
Bronze disease has nothing to do with bacteria.  It is strictly a chemical reaction.  It can spread from one coin to another because the chemicals that start it can be spread from one coin to another. 
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Offline Fides

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Re: A question about BD
« Reply #5 on: August 28, 2011, 10:01:27 am »
Apologies for labouring the point, but does that mean that if I place a coin that has BD in the same box as other coins they will also catch the BD even if never in contact?

Offline Joe Sermarini

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Re: A question about BD
« Reply #6 on: August 29, 2011, 02:34:09 pm »
If one coin you are storing has BD, where you are storing your coins may be a problem. Humidity allows BD to grow and spread. If the coins are in flips it is unlikely to transfer but I still would not store a coin with BD with other coins. 
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Offline Snegovik

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Re: A question about BD
« Reply #7 on: September 01, 2011, 10:03:49 am »
I think that bacteria was  named streptococcus monetarii.

And staphylococcus aureus eats aurei  ;D
Illegitimi non carborundum

Offline daverino

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Re: A question about BD
« Reply #8 on: September 01, 2011, 02:46:18 pm »
As I understand BD (and I think I do) it is in no way contagious from one coin to the next. Coins which were buried in acidic,oxygen-free  soil may develop an unstable layer under the patina, When dug up, they are exposed to oxygen and moisture which reacts with this unstable material to destroy the patina.

BD cannot transmit from coin to coin but the spread of this rot across the surface ( though the source of the problem is beneath) gives one the idea of a "disease". It cannot be cured but it can be stopped. The bad reaction requires moisture so, as Joe mentions, drying out your coins after you have cleaned them and keeping them dry is the best prevention.

Regards, Dave


Offline Joe Sermarini

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Re: A question about BD
« Reply #9 on: September 01, 2011, 04:03:49 pm »
YES, BD CAN TRANSMIT FROM COIN TO COIN.  The green dust that is created by bronze disease also serves as a catalyst that will start bronze disease on another coin.  That is why they call it a "disease." 
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Offline Fides

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Re: A question about BD
« Reply #10 on: September 02, 2011, 04:50:57 pm »
One final question - once, after soaking and scrubbing/picking away the green dusty encrustations, I have run into further problems. I'm left with areas where, as a result of my removal of the dusty encrustations, the metal is shining through. I think I have accidentally removed small areas of the underlying patina over which the bronze disease lay. My question is how quickly will that protective patination return to those areas of my coin? I'm very conscious that in removing *this* bout of BD I've put my coin at risk to more!

Offline Joe Sermarini

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Re: A question about BD
« Reply #11 on: September 02, 2011, 09:49:25 pm »
There was no patina under your bronze disease.  It will go to bare metal and you have to go to bare metal to get rid of it completely.  You can re-tone the bright area with a commercial product like dellers darkener or liver of sulfur.  Toning doesn't actually provide protection from the BD coming back.  For that, after treatment, apply renaissance wax and store in a low humidity environment.   

Sometimes the treatment is worse than the disease.  Some bronze disease is very active.  Light green DUST forming means it is active corrosion.  If you clean a coin and it doesn't make new dust, it isn't bronze disease or you have it in low enough humidity that it is not active.  If a coin is not making new green dust after several weeks or months (check it often), I would leave it alone.   

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Offline Fides

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Re: A question about BD
« Reply #12 on: September 03, 2011, 04:41:41 pm »
Thanks, Joe. Sometimes I don't know what I'd do without this site!

And your point about conservation after treating the disease - I have a pot of ren wax on order. But when you speak of treating the damaged patina with liver, do you mean *actual* liver? As in liver and onions?  ??? Pardon the question but I would just never have thought of using liver!

Matt

Offline Robert_Brenchley

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Re: A question about BD
« Reply #13 on: September 03, 2011, 05:52:09 pm »
Liver of sulphur is an old term for potassium sulphide and closely related compounds. It's still used by metalworkers as a name for the stuff, and it's commonly used to darken metals.
Robert Brenchley

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Offline Fides

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Re: A question about BD
« Reply #14 on: September 03, 2011, 05:55:40 pm »
Ha! That teaches me to skimread the last part of Joe's post and see 'of' as 'or'...

Thanks Rob  ;D

 

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