Another NEWP, and medal/exonumia guru advice (conservation question)

Discussion in 'World Coins' started by Stork, Jul 10, 2019.

  1. Insider

    Insider Talent on loan from...

    The discussion of "blue" copper is very simple and one day it will be solved.

    Until then, from the experience of using MS-70 on thousands of copper coins first at a major conservation service decades ago up to the conservation being done for $5 a coin (shameful advertisement) at ICG, I can report that whatever the cause, a few different chemicals will change SOME copper coins shades of blue.

    PS So far, I'm unable to tell which copper coins will turn blue UNTIL the chemicals are applied when conserving the coin. Since the original color can be restored when the conservation is finished, IDGARF how, why, when, and if it will occur. I'll leave that to the chemists above my pay grade.
     
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  3. Kentucky

    Kentucky Supporter! Supporter

    ...shameless...
    "I'll leave that to the chemists above my pay grade."
    What chemists get paid THAT good??? :)
     
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  4. GDJMSP

    GDJMSP Numismatist Moderator

    Know what I think ? I think a certain chemist whose "name" starts with K should conduct some experiments, with strict controls in place of course. Controls like swabs being used to take samples of whatever might be on a coin, swab samples taken prior to any testing on said coin. And the swabs being tested later to find out what if anything was on the coin. Then, MS70 used on the coin to see if it turns blue or not.

    The sample coins to be acquired from change, with an eye out for some that might have some kind of gunk, dirt and grime build up on them, with a few new ones from the local bank mixed in, maybe even from a roll acquired from the mint.

    Once all testing is done, a report of your results to be posted for all to see and read - with pics of course !

    AND - since you readily agree that chemist don't get paid well anyway, why you agree to do all this for free - just to reinforce your comment :)
     
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  5. TheFinn

    TheFinn Well-Known Member

    It almost looks as though the medal had had a was put on it to preserve and protect it (old thinking). That may have to come off to get down to the original surface.
     
  6. Stork

    Stork I deliver Supporter

    Indeed. I finally made it to the basement coin lair last night and will post a few photos when I get a chance to crop/resize.

    Step one: distilled water. Soaked for a bit, agitated for a bit. Manually removed a bit of 'gunk' with the help of a local thorn bush. Made it obvious a lot of what I was looking at really was just crud as discussed above. Some of the crevices had a waxy-like substance (going by using my camera set up and computer screen as my visual aid). Good thing I'm used to looking at a screen in one direction while using instruments in another without watching my hands :D.

    Interesting observation when removing the medal from the water though was the way the water 'beaded' and appeared hydrophilic like my car after the ceramic coat was applied. It just 'felt' off too.

    So, I bit the bullet and moved on to Step Two--the xylene. What an interesting aroma (yuck). The rest of the crud just melted away with only a little assistance from my favorite thorn to loosen things up and a cotton swab.

    Step three: I will not disclose whether I used a final distilled water rinse or not :D.

    I must confess I thought the color had 'gone off' when it was sitting in the xylene, but once removed from the bowl and evaporated the color was not different. It was probably a trick of my lights and using the laptop to visualize.
     
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  7. Kentucky

    Kentucky Supporter! Supporter

    Actually I am a C Carl. At a company I worked for we had two K Karls and two C Carls. At times, three of us would be in a room together and someone would walk in and call out "Carl" and all three of us would say "What?".

    Would be happy to do the sampling if you pay for the analysis. I left that equipment at work. :)
     
  8. Stork

    Stork I deliver Supporter

    Okay photo essay time.

    First I plopped it in the distilled water and let it rest a bit, then shook it around a bit. Being a tad impatient it was maybe 10 minutes. Clearly (by using my camera and laptop to visualize) there was a significant bit of 'surface yuck'. A lot just washed off.

    Sitting in the bowl and purposefully over exposed so I could see it better.
    A in bowl.jpg

    And a couple closer views. Some stuff was already off by now.
    B water detail.jpg

    and this bit was more noticeable
    C distilled water.jpg

    The reverse had some similar type sections. So, I broke out my trusty thorn and gave some of the stuff some nudges. A lot moved, but there was enough that was still very adherent. It gave an impression of being gooey/greasy/waxy some how.

    I felt like I was doing a mini-laparoscopic case...
    D thorn work.jpg

    Some close ups after removal from the distilled water--still an area of concern on the hippocamp's jawline.
    E detail.jpg

    and the drapes--tested the areas with the thorn out of the water (still soft).
    F detail.jpg

    Next up, the xylene and the result:
    combo e3e3e3.jpg

    head detail.png
    Just a bit of irregularity under the jaw, and in keeping with the rest of the medal.

    And, the drapes:
    detail drape.jpg

    Vastly improved.

    I don't have an appropriately sized airtite, so it's in a pvc-free flip in side a Coin Armour Intercept bag.
     
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  9. Pickin and Grinin

    Pickin and Grinin Well-Known Member

    This coin now needs to age.

    I would leave it open to it's surroundings for a while. Dust free environment. Maybe a cabinet, I would refrain from an envelope on a hot window sill.;)
     
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  10. GDJMSP

    GDJMSP Numismatist Moderator

    Pay for it ?? Geeez ! I did my part by coming up with the idea. The rest is up to you pal :)

    And don't gimme that excuse of I left that equipment at work - sounds suspiciously like the dog the ate my homework :D
     
  11. GDJMSP

    GDJMSP Numismatist Moderator

    Happy it worked out for ya, but to be honest I was pretty certain it would ;)

    As for some of your comments. You mentioned waxy, well, it's possible that a preservative wax was used on the medal, many used to do that in the old days - a few still do. But for the most part, in today's world anyway, wax is only used by some some ancients collectors. Wax and oils both can have a very similar look especially after a long period of time has passed.

    In any event, I still think it likely that the residue you were seeing was congealed oil of one kind or another, mixed with ordinary dirt and grime that had stuck to it over the years. And that's a very common problem with oils, or coin care products that contain oils. And even a few of the modern products still being sold contain oils. Like so many other things still common today, like many coin storage products, they should never be used.
     
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  12. Insider

    Insider Talent on loan from...

    GDJMSP said: "I still think it likely that the residue you were seeing was congealed oil of one kind or another, mixed with ordinary dirt and grime that had stuck to it over the years. And that's a very common problem..."

    Exactly. Much of the items made of bronze I see have a build-up of this type of crud in the recesses.
     
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