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2014 Gold Kennedy Proof - Copper Spotted

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  • TwoSides2aCoinTwoSides2aCoin Posts: 44,381 ✭✭✭✭✭
    edited April 29, 2020 8:49AM

    The returned item

    And a "Before" photo.
    Will try the experiment and post an after photo.



    Forgive me Miles. Wasn't trying to hijack the thread. Sharing experiences.

  • MilesWaitsMilesWaits Posts: 5,374 ✭✭✭✭✭

    No Worries!
    I really appreciate the examples that are being given for the before and after treatments.
    And that mercury gold looks like a challenge.

    Now riding the swell in PM's and surf.
  • 7Jaguars7Jaguars Posts: 7,499 ✭✭✭✭✭

    That spot at 10 o'clock on the obverse looks pretty deep, hopefully it will work

    Oh, I have done it spot up and spot down on the aluminum and it seems not to matter....

    Please report on results!

    Love that Milled British (1830-1960)
    Well, just Love coins, period.
  • TwoSides2aCoinTwoSides2aCoin Posts: 44,381 ✭✭✭✭✭

    Perhaps my next customer will be satisfied. I cannot blame my last customer. Here are the "after" photos

  • MilesWaitsMilesWaits Posts: 5,374 ✭✭✭✭✭

    Incredible difference!

    Now riding the swell in PM's and surf.
  • jmlanzafjmlanzaf Posts: 34,693 ✭✭✭✭✭
    edited April 29, 2020 5:56PM

    @jmski52 said:
    I am almost wondering if there is some other metal in the alloy that is being oxidized.

    I think that this is the case. Consider antimony, zinc, manganese - some of these may be present and might not clean up as well as Cu++

    It might not be a metal or part of the alloy at all. They do clean and prep blanks. It could be some other foreign substance on the surface. Or metal that rubbed off on the surface during handling rather than anything in the alloy.

  • jmlanzafjmlanzaf Posts: 34,693 ✭✭✭✭✭

    @PerryHall said:
    I have some questions about the sodium bicarbonate dissolved in hot water with the aluminum foil method of removing spots on gold. Do you put the side of the coin with the spot against the foil or the side without the spot against the foil or does it matter? How long does it take?

    It's electrochemical, so it shouldn't matter as long as there is good conductivity.

  • 7Jaguars7Jaguars Posts: 7,499 ✭✭✭✭✭

    TwoSides - Lovely and somewhat expected result...

    Love that Milled British (1830-1960)
    Well, just Love coins, period.
  • TwoSides2aCoinTwoSides2aCoin Posts: 44,381 ✭✭✭✭✭

    @7Jaguars said:
    TwoSides - Lovely and somewhat expected result...

    There is a small spot still, but a marked improvement.
    I did note some reaction, In the soaking period and wondered if another ten seconds might have removed what spot remains. Thanks for the tip.

  • 7Jaguars7Jaguars Posts: 7,499 ✭✭✭✭✭

    It really won't be "overexposed" by even 5 or 10 minutes.

    Love that Milled British (1830-1960)
    Well, just Love coins, period.

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