Alternatives to Verdi-Care? (Any other BD treatment tips also welcome)

Discussion in 'Ancient Coins' started by ValiantKnight, Jan 17, 2021.

  1. ValiantKnight

    ValiantKnight I AM the Senate! Supporter

    So I am currently treating a Ptolemaic bronze for the evil bronze disease, not extensive just within a small, square-shaped hole directly on the edge. I’ve had it soaking in distilled water, with me replacing the water every 3-4 days and occasionally gently scraping out any remaining/new BD within the hole. Been at it for 3 weeks and apart from a slight regrowth of BD a week into the treatment it’s been going good so far. Currently, I’d say at least 95% of the hole looks clear of BD. After this final soak my next course of action is to heat it in the oven for about an hour.

    As the title says, since Verdi-Care is nowhere to be found and seems like it won’t be for the foreseeable future (based on what I’ve read online), I’m looking for something that is just as good or at least nearly as good. Anyone have any suggestions? Also, is Verdi-Care something that stays on the coin, like Renaissance Wax? Regarding Ren-Wax (if I can’t find something like Verdi-Care), would it be wise to seal the bronze coin with it after treatment? Thanks!

    (I’m in southeast Florida by the way, to give an idea on the type of humidity I’m fighting against)
    dltsrq, DonnaML and Ryro like this.
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  3. Amit Vyas

    Amit Vyas Well-Known Member

    I have personally used Zinc dust for treating minor BD spots. The method is detailed here: https://www.collector-antiquities.c...estoring-and-conservation/bronze-disease.html

    As for commercial products, I have seen favourable reviews of Gringgott's (sold online by a US-based supplier, I believe) by a few collectors. Never mustered enough courage to buy myself what would look like small packets of unidentified white powder to customs officials checking the mail. :-D
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  4. Kentucky

    Kentucky Supporter! Supporter

    I worked in a textile department for awhile and my boss had to go to Switzerland to visit a company we were consulting with. For the return trip, he had his attache case loaded with baggies of polymer samples...finely divided white powders. The customs guy asked to see one, and as he opened the case, he thought of what it looked like :nailbiting::nailbiting::nailbiting::vomit: Luckily he had one sample that was large chips and he plopped it out for the customs guy and said a silent prayer.
    Alegandron, ominus1 and Amit Vyas like this.
  5. Kentucky

    Kentucky Supporter! Supporter

    Send @BadThad a PM and see if he can help you.
    yakpoo likes this.
  6. gsimonel

    gsimonel Supporter! Supporter

    You need to be careful about sealing a coin after treating it for BD. You don't want to seal in any remaining traces of the cuprous chloride and moisture. If you bake the coin, you will probably drive out any moisture and be okay, but just to be sure, I recommend you let your coin sit out someplace where you am likely to see it often. If there are no traces of returning BD after a month or two, then you can assume the coin is cured and coat it with anything you like. Or, like I do, just put it back into a flip and return it to your collection.
  7. otlichnik

    otlichnik Well-Known Member

    I agree with gsimonel. In a drier climate it is sometimes ok to risk sealing after a good clean and "bake" (oven at 200 F to drive out remaining moisture). The sealing can work to keep out the moisture that interacts with the cuprous chlorides thus preventing the formation of new BD.

    But in a humid climate that is almost always doomed to failure as it is so hard to be sure you have all the moisture out before the wax is applied. Any remaining water molecules can then continue to react with the cuprous chlorides under the sealant and you have big problems.

    I have used benzotriazole in a few cases. Do some research to see if you are interested in it and then a whole lot more research before using it. It is a hazardous chemical - though that just means gloves and avoid indoor spaces, but it its easy to use safely out of doors. Because it is hazardous it might not be sold in your venue. It can be had as a powder which needs mixing in something (I can't recall what). But I avoided that and found it as a small vial of liquid. You still need to clean the item first, but it then bonds with the copper and forms a sealant preventing more BD. It is different from a wax sealant as it apparently involves the upper layers of the copper atoms - don't ask me how.

    Not something I recommend lightly, but a hole in the side of a coin kept in a humid environment is exactly the sort of scenario it is good for.

    DonnaML likes this.
  8. hotwheelsearl

    hotwheelsearl Well-Known Member

    Depend how bad it is. Extreme verdigris comes right off when treated with lye.
    DonnaML likes this.
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