My first case of Bronze Disease

Did you throw it over your shoulder for good luck?

Aussie, you of course benefit from having the coin in hand and pictures cannot tell the whole story. That being said, those light blue/green spots in the treated areas still look 'active'. Judging from the coin's history I would continue treatment for BD. Just my two denarii worth.

 

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suggest you get some desiccant similar to this

https://www.amazon.co.uk/Dry-Packs-...=1473165284&sr=1-5-catcorr&keywords=dessicant

When it changes colour, put it in the microwave to renew it.

 

Considering how bad it is, is there a chance you can get a refund? Many dealers on VC are nice enough may let you do so, or at least give store credit. I had a few let me return BD tets.

Told you!

If you compared us to the "Three Bears", Forvm is too stuffy/rule ridden, CU is pretty slow, and CT is just right!!

 

Well now I'm confused....At first glance at the 'treated' photo I would've thought a further 'treatment' was necessary as TIF did---now I'm I'm not so sure after all the additional posts.

I'd reach out to the seller and inquire about a 'replacement' as Mat suggested.

 

I am a novice at ancient coins, but I am a chemist and wanted to pass along some information:
Sodium sesquicarbonate is a double salt of sodium carbonate (washing soda) and sodium bicarbonate (baking soda) and a solution of the sesquicarbonate is the same as a solution of a mixture of the two.

The original coin was very attractive, but the conservation method appears to have removed a lot of material and been detrimental to the appearance of the final coin. Too bad you can't start over, one of our members @BadThad has a product, VerdiCare, that stabilizes bronze disease with minimal coin damage. If you get some and apply it, I don't think it would hurt the appearance of the coin and might prove to be beneficial. Good luck with it.

 

A couple of things. One, green patinas can often be very brittle and will flake away quite easily. Most Europeans will pay an extreme premium for those greens, but often they are quite delicate, and often powdery (which explains why so many people might think it is bronze disease).

Second, and this is MOST important, there likely wont be (I dont know any personally who will do so) ANY dealer who will take a coin back after you have altered it in any way. If you take it upon yourself to clean or treat a coin, no matter what your intent may be, good or bad, a dealer just isn't going to take it back. Kind of like the idea of 'you break it you buy it'.

Bronze disease is a weird thing. It can happen at any time and nobody really knows exactly why. People often talk about humidity, storage, etc., but it can pop up randomly. A dealer sells a coin honestly and honorably, but two weeks or two decades later it develops this condition. Are they liable? I dont think so, and I have been a dealer for nearly three decades.

Have I sold coins with this condition? Absolutely. But with full disclosure. I once had a nice group of Judaean bronzes I bought from David Hendin. I stored them properly for a few years before I got around to looking at them. In the interim they had developed this problem (and since they were stored in a bag, all the connecting coins developed the problem). I didn't go back to Dave for a refund, I accepted that it simply happened. I subsequently donated them to an individual who was experienced in treating the problem and he in turn donated the coins to the Ancient Coins for Education project. Off to school kids to promote history and learning. Pretty good outcome, I would think.

 

Thanks for all of your thoughts and replies on this, I am happy to keep the coin and would not consider asking for a refund as I look at it as my problem now, as it was their's (dealer) when they owned it. This thread was just to show for interest the various outcomes in treatment, to me it is still a good coin and didn't cost much, I will post it again in the future if I get it looking a bit better.

 

Not a bad idea Pishpash, how many do you think I would need for a safe 18''x 18''x 10'' high, just a guess would be good enough if possible.

 

I would get a couple and see how you go. If you get the ones that change colour, you will get an indication on how often you will need to "recharge" them. Get more as you need them.

 

Thanks very much Pishpash I will get two and see how I go.

 

Ancient Aussie ... man, I love your coin table (it's sweet!!)



It kind of reminds me of chrsmat's old beauty (gawd, I miss that gnarly ol' table)

 

The recipe I have suggests 4.24g carbonate and 3.36g bicarbonate in 100ml water for a weak solution doubling the salts for a patina stripper for hard cases. Do you see this as appropriate or am I missing something? Does either of the salts take on enough water from the air that it would mess up the proportions?

 

Wow, being more chemical than I was. Looks good.

 

This is the mixture and info sheet I went of, trying to save the patina as soon as possible but alas, green water almost from the start.
Sodium Sesquicarbonate
Place the coins in a glass container and fill with a 5% solution of sodium sesquicarbonate. Let them soak for about 14 days, replace the solution, and soak for another 14 days. Then, place the coin in distilled water for about a week.
Don't have sodium sesquicarbonatelying around? You can make it with equal molar amounts of sodium carbonate (also called soda ash) and sodium bicarbonate (yes, you know what that is). For example, a 5% molal solution would be 10.6g of carbonate and 8.4g of bicarbonate in 100ml of water.
A 5% solution WILL REMOVE any "patina" on the coin! If there is an exceptionally aesthetic "patina" to be preserved, try a 1% or 2% solution. Be warned, though, that it will take three times as long, and has a higher risk of being ineffective.
The Beauty of a Green Patina … Can be completely stripped off through cleaning!

 

As the chemists will tell you, BD is not a disease , it is chemical reaction and as such it can not jump from one coin to another innocent one just nearby. What is happening is that both coin are in an environment that enhances the chemical reactions. Water vapor, high temperatures, energetic light source ( sun, uv-rich light), other chemicals used to clean them, etc. The environment isn't just part of the cause, it is the vast majority of the cause. Try this, put a BD coin into a zip lock bag and squeeze all air out and zip it. Do the same with a non-BD coin. Then put both into a 2nd zip lock bag with some modern zinc cents that you have scrubbed the heck out with a scrubber and seal it. The 100% scrubbed copper shell on the cent will react faster than the other coins surface. When the cents turn ugly with beginning corrosion, spend them and replace with newly scrubbed ones. Sacrifice the cents and protect the others. I have several older safes that are not air tight. I live in a desert that has occasional monsoon periods. I do not have any desiccation devices in any of them , just sacrificial cents, and I have no bronze disease type of corrosion since starting that many years ago. Only costs a few cents. I do replace the outer bag when changing cents. I have bought zip lock bags big enough for several old fashioned coin albums, and same results. I know that some US collectors will lament using 'valuable' copper/zinc moderns, but ancients should have no such problem. I would and do use Thad's stuff on any similar corrosion. It can't stop BC ( Bronze cancer), but best for the purpose ( IMO). Jim

 

Dictionaries will tell you that a disease is an abnormal condition that affects the normal function of all or part of an organism. Substitute 'coin' for 'organism'. In truth disease is not abnormal but part of the very normal process of brogression between birth and death or mining and return to a pile of powder. Ashes to ashes, dust to dust. It is rather like the word 'weed' which is best defined as a plant growing somewhere you don't want it to grow. Soybeans are weeds in corn fields and visa-versa. Chemists who deny BD its status are making up their own definition. Mine is 'something that makes you sick'. BD makes me sick just thinking about it, ergo...

 

VD and BD are two things that require immediate attention ...



... I'm just sayin'

 

Molal...wow, YEARS since I have seen that term, however it would have no meaning coupled to %. The solution of basic chemicals remove the patina by removing the Cu salts, and of course that removes the copper. If they are REALLY far gone, perhaps VerdiCare might work better, perhaps @BadThad can speak to that.

 

BD is a term coined by the ignorant. It is NOT a disease, it is corrosion (verdigris) pure and simple. In the world of verdigris, it is simply another type, HCl induced. Chemists whom deny "BD" are not making up a definition, coin folks that use and perpetuate the term made-up the definition.....which is utterly incorrect in the world of metals and chemistry.

In my 16 years working in the metalworking fluid industry, I have yet to have a customer call and say "we have bronze disease", can you help? Nor have I ever heard ANYONE in either industry use the term, nor have a read any papers, nor heard any lectures at trade shows about "bronze disease". Why? Because there is no such thing.

 

That's not surprising, nor is it upsetting. "Bronze disease" is a hobby-specific colloquialism. I'm fine with that.