Can 'Sodium Carbonate' be used as 'Sodium sesquicarbonate' to treat Bronze Disease?

Kentucky (and others) said "Sodium sesquicarbonate is the accepted treatment for bronze disease"

As Sodium Sesquicarbonate does not appear to be readily available in Australia,
can some of you learned people please tell me "Can Sodium Carbonate be used to replace Sodium sesquicarbonate in the treatment of Bronze Disease?"

 

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The carbonate soda is in Woolworths called
Lectric Washing soda and also Bi-Carbonate is the packet on the left already opened (destroyed label) see pic below.

 

Sodium Sesquicarbonate is equal molar parts of sodium carbonate (Na2-CO3) and sodium bi carbonate (Na-CO3-H). You can make Sesqui by mixing equal (molar) parts of Na2CO3 and NACO3H. I found a couple of links on treating bronze disease:

http://www.crescentcitycoinclub.org/seminars_and_programs/Bronze Disease.pdf

http://www.accla.org/actaaccla/bronzediseasetherapy.html

I will have to use the treatment on a coin or two I have.

 

I did not realise that you could make your own. Thank-you.
Forgive my ignorance but I am not familiar with the term 'molar' when used in this context. ('Google' is no help and a 'molar' to me is a tooth.) Can you please explain the word, in this context, to me? Thank-you.

 

Molar is the number of moles (6.02 X 10-23 power). Alot of atoms. Just look up the molecular weight of sodium carbonate and sodium bicarbonate and add in grams that number of each to 1 litre of distilled water and disolve. Or, just disolve some baking soda in water and soak the coin in it. It will neutralize any acids and loosen any verdigris that would come off. Before using it though, I would treat the coin with xylene or methylene chloride to get off any PVC so it will work.

 

Try 10.6g carbonate and 8.4g bicarb in 100 ml distilled water. That is not quantitative chemistry but is something most can measure with their coin scales. That recipe could harm 'good' patina so you might dilute it with more distilled water if you are trying to avoid stripping everything.

 

Reading the articles that rrdenarius' has linked to has given me pause. If you can buy the sodium sesquicarbonate (SSC) on eBay inexpensively--I checked, and you can--why bother mixing your own?

Furthermore, I've successfully treated coins with bronze disease (BD) using just distilled water (DW) with the following method:

Brush off any BD. Get off as much as possible--use compressed air, a toothpick and/or a pointed brass pick. Use a loupe or a stereo microscope if you have one.

Place the coin in 6 to 8 oz. of DW for 24-48 hours, then dump out the DW and replace it with fresh. Continue doing this for 2-3 weeks, changing the water every 1 or 2 days. In most cases, your coin will be cured.

BUT: I recommend setting the coin out somewhere where you will see it often. Check it carefully and frequently to make sure there is no sign of the BD returning. If there is, repeat the above treatment. Over the years I've had to treat a couple of coins twice to completely remove the BD. I've never had to treat one a third time, though. Since a gallon of DW can be gotten cheaply from any grocery store, maybe try this method first to see if you even need to use SSC.

 

Do coins made of pure copper get bronze disease? They certainly do get raised greenish corrosion that LOOKS like bronze disease. Would the treatment be the same?

 

No coin is pure copper, although some are pretty darn close. But they all contain trace metals.

But more to the point, bronze disease is caused by the copper reacting to hydrochloric or hydrosulfuric acid, which is created when moisture in the area reacts with chemicals in the environment--environment meaning the air, the dirt that it was buried in, or even just hanging around on the surface of the coin. So yes, given the right conditions, copper coins can succumb to bronze disease.

Just don't confuse bronze disease with the natural green patina that forms on the surface of a copper object over time. Patina is good for the object, BD is bad. If you can easily brush it off with a toothbrush, it's BD. Bad. If you can't, it's patina. Good. If it raises up above the surface, that's bad, too. Patina will just coat the surface and not change the topology. Good.

 

Thanks.

 

By the time you add the ridiculous 'eBay' postage $100 ($99.88) it is not so cheap.

 

That postage is a gouge.
Try Amazon.
https://www.amazon.com/Sodium-Sesqu...320874&sr=8-1&keywords=sodium+sesquicarbonate

 

Quoting from @gsimonel "If you can buy the sodium sesquicarbonate (SSC) on eBay inexpensively--I checked, and you can--why bother mixing your own?"

I have sodium bicarbonate in my refrigerator and on the shelf in my kitchen. Sodium carbonate or washing soda is available at the grocery store. @dougsmit gave you the amounts, solution can be diluted so as to give slower action.

 

I looked there, but the item that came up states that they do not ship to Australia.
THAT is why I will mix my own.

 

Alka Selzer?

 

Alka-Seltzer contains three active ingredients; aspirin (acetylsalicylic acid) (ASA), sodium bicarbonate, and anhydrous citric acid. The aspirin is a pain reliever and anti-inflammatory, and the sodium bicarbonate and citric acid form an antacid by their effervescent reaction with water.

 

Yup, BD really hurts.....

 

This is good advice. No need for mole to mass calculations.

If you are intent on making it yourself...

An alternative to sodium sesquicarbonate can be produced by making 50/50 molar ratio of sodium bicarbonate and sodium carbonate.

In terms of grams, you can use the following mass ratio: for every 1 gram of sodium bicarbonate use 1.26 grams of sodium carbonate. Just be sure to use 'anhydrous' sodium carbonate. If you use hydrated sodium carbonate, then you will need to change this ratio.

 

It really helps to read the posts...I didn't say that, the quotation marks denote that I was quoting someone else. Go back and read what I said. A mole to most people is something that you kill in your yard or tell your doctor if it starts to grow hairs and gets bigger. Someone has already posted the correct molar ratio, but yours is BACKWARDS. Check post #6 where @dougsmit posted the correct amounts. "Anhydrous" "Hydrated" if it is hot, make sure you keep yourself hydrated so you don't become anhydrous (and hopefully not androgynous).

 

I can buy a box of washing soda here for less than $5, and a box of baking soda for less than a dollar, and I don't have to wait for delivery.

I keep washing soda on hand anyhow, because it's good for killing odors in exercise clothes. Just dissolve 10-20g (maybe a tablespoon) in a tub of water and soak the clothes in it for a few hours. It reacts with the fatty acids and esters that cause most of the odor. Rinse, dry, presto, odorless clothes.