Featured Correct way to make 5% solution of sodium sesquicarbonate for Bronze Disease treatment.

Discussion in 'Ancient Coins' started by Theodosius, Jan 3, 2019.

  1. Theodosius

    Theodosius Unrepentant Fine Style Freak! Supporter

    Thanks @-jeffB I should have mentioned using glass for acetone!

    I found out the hard way what it does to plastic myself. :)

    I also cover the acetone all the time because it evaporates so fast.

    John
     
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  3. kaparthy

    kaparthy Well-Known Member

    I was sort of disappointed because the formula for sodium sesquicarbonate was not given the way they did that for the copper chlor*s. I am a big fan of kitchen chemistry.
     
  4. Deacon Ray

    Deacon Ray Supporter! Supporter

    Thank you for tackling a scary demon, @Theodosius ! Like human health issues, perhaps we need an annual Bronze Disease Awareness Month here on the Ancients Forum. I discovered a coin that I suspected of having bronze disease a couple of years ago and didn’t accept it as a teaching /learning opportunity. I let fear and denial control my actions and I wound up giving the coin a burial at sea and threw it into the ocean. Today, I wish that I hadn't done it. 1. It may not have been bronze disease and 2. It may have been a minor case and salvageable.

    Here’s a video demonstrating another option for a coin with BD. I'm not recommending this but it might be a fun project.

     
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  5. Hookman

    Hookman Well-Known Member

    I gather that these treatments are primarily for Ancient coins and not for modern ones. I collect mostly silver with a few 18th, 19th and 20th century bronzes and coppers now and then.

    Is BD something I need to worry about or be concerned with? I don't know that I've ever seen any BD on any coin I've collected.

    Please correct me if I'm wrong or educate me if I need it.

    Thanks. This is a very informative thread.
     
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  6. Theodosius

    Theodosius Unrepentant Fine Style Freak! Supporter

    BD can happen to modern bronze coins. I am treating a US large cent right now. There is a product called Verdicare that is good for the low level infections most modern coins have. You can find it by googling. The easy way to recognize BD is that it has a light green powdery appearance that is easy to flake off with a toothpick.

    John
     
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  7. Hookman

    Hookman Well-Known Member

    Thanks John. I'll need to look over my coins.
     
  8. Topcat7

    Topcat7 Still Learning

    @Theodosius
    Thank-you, John. I am one of those who has accumulated 100's of 'tried and true' Treatments For Bronze Disease.
    I have now downloaded your tutorial and deleted the rest.
    Thank-you, again.
     
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  9. Theodosius

    Theodosius Unrepentant Fine Style Freak! Supporter

    Just out of curiosity I decided to test the mixing directions from Forum. You sometimes learn useful things by testing for yourself the information you read.

    I have no way to test the making of sodium sesquicarbonate from their directions, but I could test their mixing ratio:

    “Mix 2 tablespoons of soda mix to three cups of water”

    Looking at a measuring cup graduated in cups and milliliters followed by some google searching, I found that 1 cup of water is about 235 milliliters.

    So, 3 cups of water equal 705 milliliters, call it 700 for simplicity.

    I decided to use @Hookman 's idea of zeroing the scale. Here is my high-tech apparatus.
    20190104_205403.jpg
    I measured out 2 level tablespoons of sodium sesquicarbonate.
    20190104_205111.jpg
    Which turned out to weigh 26.78 grams.
    20190104_205130.jpg
    This equals a 3.7% solution, 26.78 / (700+26.78) = 3.68%.

    This is less than the 5% concentration recommended, which I think is much better than if it were significantly more concentrated than 5%.

    Next, I measured out 2 (very) heaping tablespoons.
    20190104_205738.jpg
    Which turned out to be 46.12 grams.
    20190104_205752.jpg
    This yields a 6.2% solution, 46.12 / (700 + 46.12) = 6.18%.

    This is more concentrated than recommended, but probably not dangerously more.

    That is an interesting difference in results depending on whether you interpret “tablespoon” as level or heaping. Now most bakers will tell you that unless the recipe specifically calls for “heaping” or “rounded”, then use level tablespoons. Another clue is that a tablespoon is defined as 15 milliliters of liquid, try making a heaping tablespoon of water sometime.

    Overall, I would rate the Forum directions as pretty good.

    John
     
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  10. -jeffB

    -jeffB Greshams LEO Supporter

    It's easier than you think, thanks to surface tension!

    meniscus_2.jpg
     
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  11. Nyatii

    Nyatii I like running w/scissors. Makes me feel dangerous

    Well Jeff, that explains something that I've been wondering about......
    I have surface tension......

    Sorry, couldn't help myself...got off tract...
     
  12. TIF

    TIF Always learning. Supporter

    That is hilarious! I'm going to have to use that line sometime. No one else will understand it but I'll laugh :D.
     
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  13. TONYBRONX

    TONYBRONX Well-Known Member

    What about using this one a red uncirculated 1901 Indian head cent with two dots right above the date, they seam to have penetrated the surface of the coin and in those areas and are green.
    Thanks for any advice.
    Anthony
     
  14. TONYBRONX

    TONYBRONX Well-Known Member

    What about using this one a red uncirculated 1901 Indian head cent with two dots right above the date, they seam to have penetrated the surface of the coin and in those areas and are green.
    Thanks for any advice.
    Anthony
     
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  15. Andrew McCabe

    Andrew McCabe Well-Known Member

    i don't want water anywhere near my bronze coins. I use benzotriazole 5% mixed with pure alcohol. It works well. For those who do use a water solution, I'd emphasise that distilled water isn't a nice option but rather absolutely essential. Tap water is full of nasty chlorides. For me tho, water of any kind is a no-no.
     
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  16. desertgem

    desertgem MODERATOR Senior Errer Collecktor Moderator

    Tony, photos would help, although very high probability they are copper oxidation ( corrosion). Whether active PVC ( little more bluish usually) or just environmental is difficult to suggest on that old a coin without a close up. If it is PVC it is very soluble in acetone ( use search to find a thread where the use is discussed. If not then this thread offers some info. My go-to is Verdicare or other chemicals produced by BadThad a member here.( IMO) Jim
     
  17. RICHARD K

    RICHARD K MISTY & SASHA

    I thought cleaning coins was a no no ?
     
  18. Orfew

    Orfew Supporter! Supporter

    You are in the ancients section. All ancient coins are cleaned to a certain extent. It is not a bogeyman for collectors of ancients. We also handle our coins often. Both of these are reasons I do not and will not collect modern coins.
     
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