Victoria Copper "cleaning" experiment

Discussion in 'World Coins' started by Mark Metzger, Dec 29, 2019.

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  1. GDJMSP

    GDJMSP Numismatist Moderator

    Unless you catch the angle and the light just right - you won't be able to see them. Which of course is why many, many people claim they do stuff like this all the time and cannot see any damage.

    But consider this, think about what verdigris is. It is what metal was turned into by corrosion, a fine granular substance. A granular substance that in effect is rubbed over the surface of the coin by the action of the brush. Even if you discount the effects of the brush itself entirely, and there will always be effects from a brush, any brush, can you even imagine how doing such a thing as rubbing a granular substance across the surface of a coin cannot result in hairlines and fine scratches on the coin ?
     
    GDJMSP, Dec 31, 2019
    #21 + Quote Reply
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  3. Seattlite86

    Seattlite86 Outspoken Member

    I honestly can't imagine there wouldn't be any hairlines, so I'm trying to understand why the EAC president would claim it safe. Let's assume for fun that the verdigris was lifted off the coin and only the brush touched the surface. That would be the only conceivable way in which the verdigris was not scraped along the surface, leaving just the brush. @Mark Metzger you have the coin in hand, what do you see upon closest inspection?
     
    Seattlite86, Dec 31, 2019
    #22 + Quote Reply
  4. GDJMSP

    GDJMSP Numismatist Moderator

    It's pretty simple, it all depends on what your definition of "safe" is.

    You'll find books, articles, quotes, and even live talks where some of the most respected names in numismatics say all kinds of things are "safe". But that doesn't mean they actually are. You'll also find countless quotes of them saying that when struck the metal of the planchet flows outwards towards the rims. And that's not only patently untrue it's physically impossible.

    All ya have to do to realize what I said is true is ask yourself 1 very simple question - where does the majority of the metal end up when a plachent is struck ? Answer, it ends up in the center of the coin.
     
    GDJMSP, Dec 31, 2019
    #23 + Quote Reply
    Seattlite86 likes this.
  5. Seattlite86

    Seattlite86 Outspoken Member

    I agree that safe and acceptable are relative terms. There's a reason some cleaned coins get a pass by TPGs and others don't. I guess I'm trying to figure out what my level of acceptable is. If there aren't obvious hairlines on Mark's coins, I would consider his efforts acceptable in my book. The coin is improved and the surface does not look more impaired than it already was. If anything, it looks better.

    As far as metal flowing to the rims... no doubt the metal can most easily flow to the center, where the most space is, but unless the collar is the exact same size as the planchet, some metal should inevitably flow outward. That being said, it makes sense to say that the metal is flowing towards the center though, as the flow lines are going to be from the metal rushing to the center. I'll be more careful in my explanation of metal flow when I share it in the future.
     
    Seattlite86, Dec 31, 2019
    #24 + Quote Reply
  6. Maxfli

    Maxfli Well-Known Member

    I think you would've gotten better results — with less effort and less risk — using a xylene soak followed by a Verdi-Care application.
     
    Maxfli, Dec 31, 2019
    #25 + Quote Reply
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