My first case of Bronze Disease

@Ancient Aussie, if you are reluctant to re-treat with sodium sesquicarbonate, perhaps a compromise would be to treat with VerdiCare and check the coin every week or two. If you apply a generous amount of VerdiCare and let it soak for a while (overnight), rubbing occasionally with a VerdiCare-soaked cotton tip swab, the bright green will darken which may improve the appearance.

Recently I treated some early-stage BD coins with VerdiCare letting them soak overnight. On one, the previously green areas turned reddish and hard. I don't remember which copper compound is red, but I guess the VerdiCare converted some of the cuprous chloride to copper-something-else.

 

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I am not convinced the purple patches were BD. These sort of patches can be seen frequently on ancients and is usually just a patch of red oxide which has stabilised. I think the coin was waxed or had some sort of coating put on by the dealer......
I would not have treated the coin initially, but would have left it as It had no obvious green fluffy holes or deposits. It seems that having placed the coin in SSC you have removed the surface protection and allowed the coin surface/patina to dry and break down.

 

Thanks TIF that's the sort of help I am after, I either destroy the patina completely or I do something like you just suggested.

 

Yes I agree YOC those purple areas were probably covered with something but remember I placed it in SSC AFTER BD had broken out in the areas, which leads me to believe it was the high humidity in my house that got it going after it was presumably stabilised by the dealer.

 

Do you have any pictures taken at the time you think the BD broke out.

 

once you are sure the Bd has gone a light rub with renaissance wax will darken the patina again and protect it.

 

No unfortunately YOC I wasn't a member of coin talk then and didn't think of taking a pic then, but no matter what I decide to do with it down the the track I will show you the reults.

 

Again that's another option and good advice.

 

Just keep it dry, wait and watch and after a while renaissance wax it. Thats what I'd do, for what its worth.

 

I think the coin was previously treated for BD. The circled areas appear to be relative pits.



This is one of the difficult things about bronze coins. Apply/creating a new patina is often part of the cleaning/conservation process. There are many ways to make a new patina and I think some of the recipes or coatings cause or accelerate bronze disease, or perhaps just hide inadequately treated BD. I generally can't tell by looking at a coin how the patina was made, if it is "original", and if the new patina could be harming the coin or hiding ongoing corrosion.

I treat most of my bronze coins upon arrival unless they look impeccable or unless there are different pictures of the coin over time proving stability. At minimum, they get a light coat of Verdicare. If they have any loose dirt or sandy stuff (or something that looks like colored wax or makeup), I first soak it in water, then try rubbing alcohol, and then perhaps mineral spirits. Once anything that has been applied has been removed, if there are any suspicious areas I poke at them to check the stability. After a thorough soak in distilled water and thorough drying, I apply Verdicare and then store in a sealed safe with a desiccant.

I check my coins fairly often, and usually I have a few which need some Verdicare or treatment.

 

If I had of left the coin for another week it would have eaten a hole through the coin as it is at the moment there is a crater 2-3mm deep.

 

Yes, the difficult-to-use platform keeps me away. Simply typing and attaching pictures isn't hard, but if you want to do any formatting (and I always do), it is very tedious.

CoinTalk's platform is fantastic!!

 

Yes I reckon your right TIF as I was always wondering how did I get that for $64. I ended up taking that whole plastic sleeve out of the album just to make sure it didn't contaminate any other coins.

 

The patina looks original to me. It looks like the patina was very fragile though and the BD saw a chance and took it. The cleaning methods employed by some dealers are what invite BD in....usually acid. repatination may seal in the problems, but rarely cause them....

 

I think the environment has a lot to do with it, like presumably had dormant bronze disease when I got it and then all of the sudden exposed to high humidity sparked it off again, That makes me wonder what happens in a month or two when I turn the evaporative cooler back on........do I lose the rest of the coin or should I do what TIF is thinking....throw the bloody thing away.

 

I wasn't thinking that at all! It just needs some TLC and close observation I have many coins which came in similar or worse condition and many coins which require close observation and sporadic treatment.

As much trouble as my bronzes cause, occasionally I consider only collecting silver and occasionally EL and AV.

There are just so many interesting bronzes though, and the usually lower price is welcome.

 

Plus, silver coins have the added benefit of being quite beautiful. Not that I'm biased or anything.

 

Well, not being an expert, I don't see BD. I see a coin that was made to look different (better) for sale. If that were BD, the results would be much different IMHO. Here is a coin I purchased years ago that "caught" BD and the resulting damage after treatment. I do not have a before image.