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Elements

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Reputation Activity

  1. Haha
    Elements reacted to Shinus73 in Is anyone here a tightar*e like me   
    I’m tight, but if I told my wife I’d made her some soap so we didn’t have to buy any, the torrent of abuse would be one for the ages.
  2. Like
    Elements got a reaction from tallthinkev in Red spotted/finger printed proof sovereigns   
  3. Like
    Elements got a reaction from Roy in Red spotted/finger printed proof sovereigns   
  4. Like
    Elements got a reaction from Roy in Red spotted/finger printed proof sovereigns   
    After:
    Not perfect but almost all spots removed. With more time maybe I could completely remove them







  5. Like
    Elements got a reaction from CadmiumGreen in Red spotted/finger printed proof sovereigns   
  6. Like
    Elements got a reaction from CadmiumGreen in Red spotted/finger printed proof sovereigns   
    After:
    Not perfect but almost all spots removed. With more time maybe I could completely remove them







  7. Like
    Elements got a reaction from Fathallazf in Red spotted/finger printed proof sovereigns   
  8. Like
    Elements got a reaction from Serendipity in Red spotted/finger printed proof sovereigns   
    see these academic papers. XPS is a great analytical instrument but prohibitively expensive bit of kit
    It and other techniques likely point to silver sulfide, but can’t rule out copper oxide.
    https://www.zlate-cihly.cz/Red_dot_on_coins_surface.pdf
    https://www.researchgate.net/profile/Saulius_Kaciulis/publication/234224608_Gold_corrosion_red_stains_on_a_gold_Austrian_Ducat/links/0deec52deb060ed2a1000000/Gold-corrosion-red-stains-on-a-gold-Austrian-Ducat.pdf?origin=publication_detail
    https://www.sciencedirect.com/science/article/abs/pii/S0168583X12007987
    https://www.sciencedirect.com/science/article/pii/S1001052107600308
     
    The chemistry is similar to that well known for removing tarnish from silver coins, since the tarnish is likely Ag2S in both cases looking at the above research papers (even if it’s copper the same process works) a similar treatment should and did work.
    To find out why the chemistry behind the silver tarnish removal (and similar process here) I point you to redox potentials of the reactions:
    Cu2O(s)+H2O+2e- <—> 2Cu(s)+OH-        -0.36
    Al3+ + 3e- <—> Al(s)                                   -1.662
    Ag2S(s) + 2e-   <—> 2Ag(s)+ S2-(aq)       -0.69
    The more negative the potential the more the equilibrium lies to the left. Since Al can easily donate electrons to either silver sulfide or copper oxide it can reduce either.  Another forum member did this recently on his libertad and worked, the above is the reason why.
    @Serendipity
  9. Like
    Elements reacted to h103efa in Red spotted/finger printed proof sovereigns   
    Biochem Rules!
    I certainly enjoyed seeing some chem redox reactions on here @Elements
    I'll also have a good look at some of the journal links and corresponding citations/references. I'll also go see some of the chem guys at work and see what they have to say!
  10. Like
    Elements got a reaction from h103efa in Red spotted/finger printed proof sovereigns   
    see these academic papers. XPS is a great analytical instrument but prohibitively expensive bit of kit
    It and other techniques likely point to silver sulfide, but can’t rule out copper oxide.
    https://www.zlate-cihly.cz/Red_dot_on_coins_surface.pdf
    https://www.researchgate.net/profile/Saulius_Kaciulis/publication/234224608_Gold_corrosion_red_stains_on_a_gold_Austrian_Ducat/links/0deec52deb060ed2a1000000/Gold-corrosion-red-stains-on-a-gold-Austrian-Ducat.pdf?origin=publication_detail
    https://www.sciencedirect.com/science/article/abs/pii/S0168583X12007987
    https://www.sciencedirect.com/science/article/pii/S1001052107600308
     
    The chemistry is similar to that well known for removing tarnish from silver coins, since the tarnish is likely Ag2S in both cases looking at the above research papers (even if it’s copper the same process works) a similar treatment should and did work.
    To find out why the chemistry behind the silver tarnish removal (and similar process here) I point you to redox potentials of the reactions:
    Cu2O(s)+H2O+2e- <—> 2Cu(s)+OH-        -0.36
    Al3+ + 3e- <—> Al(s)                                   -1.662
    Ag2S(s) + 2e-   <—> 2Ag(s)+ S2-(aq)       -0.69
    The more negative the potential the more the equilibrium lies to the left. Since Al can easily donate electrons to either silver sulfide or copper oxide it can reduce either.  Another forum member did this recently on his libertad and worked, the above is the reason why.
    @Serendipity
  11. Confused
    Elements got a reaction from 1817Karl in Red spotted/finger printed proof sovereigns   
    see these academic papers. XPS is a great analytical instrument but prohibitively expensive bit of kit
    It and other techniques likely point to silver sulfide, but can’t rule out copper oxide.
    https://www.zlate-cihly.cz/Red_dot_on_coins_surface.pdf
    https://www.researchgate.net/profile/Saulius_Kaciulis/publication/234224608_Gold_corrosion_red_stains_on_a_gold_Austrian_Ducat/links/0deec52deb060ed2a1000000/Gold-corrosion-red-stains-on-a-gold-Austrian-Ducat.pdf?origin=publication_detail
    https://www.sciencedirect.com/science/article/abs/pii/S0168583X12007987
    https://www.sciencedirect.com/science/article/pii/S1001052107600308
     
    The chemistry is similar to that well known for removing tarnish from silver coins, since the tarnish is likely Ag2S in both cases looking at the above research papers (even if it’s copper the same process works) a similar treatment should and did work.
    To find out why the chemistry behind the silver tarnish removal (and similar process here) I point you to redox potentials of the reactions:
    Cu2O(s)+H2O+2e- <—> 2Cu(s)+OH-        -0.36
    Al3+ + 3e- <—> Al(s)                                   -1.662
    Ag2S(s) + 2e-   <—> 2Ag(s)+ S2-(aq)       -0.69
    The more negative the potential the more the equilibrium lies to the left. Since Al can easily donate electrons to either silver sulfide or copper oxide it can reduce either.  Another forum member did this recently on his libertad and worked, the above is the reason why.
    @Serendipity
  12. Like
    Elements reacted to sovereignsteve in Red spotted/finger printed proof sovereigns   
    Thanks for the tag, this is something I have a definite interest in as I am a bit of a chemist but more of a biochemist in reality.
    I will spend a little time studying the links you gave and then perhaps I will have a few questions😊
  13. Like
    Elements got a reaction from Penfold in Red spotted/finger printed proof sovereigns   
  14. Thanks
    Elements reacted to richatthecroft in Red spotted/finger printed proof sovereigns   
    My oh my- that was a challenge- nasty was an understatement- but a great opportunity to experiment.  
    The difference post treatment is amazing.   
  15. Thanks
    Elements reacted to JunkBond in Red spotted/finger printed proof sovereigns   
    Fantastic, even the scratches on the obverse seem less evident. Well done.
  16. Thanks
    Elements reacted to Miganto in Red spotted/finger printed proof sovereigns   
    Looks amazing - would be good to see if there's a longer term effect on the coin by doing this.  Update us again in 10 years please
  17. Thanks
    Elements reacted to Provvidenza in Red spotted/finger printed proof sovereigns   
    Very impressive. the treated coin looks amazing. 👍
  18. Thanks
    Elements reacted to daca in Red spotted/finger printed proof sovereigns   
    @Elements extraordinary work . completely different coin.
  19. Like
    Elements got a reaction from daca in Red spotted/finger printed proof sovereigns   
    After:
    Not perfect but almost all spots removed. With more time maybe I could completely remove them







  20. Thanks
    Elements got a reaction from kimchi in Red spotted/finger printed proof sovereigns   
  21. Like
    Elements got a reaction from daca in Red spotted/finger printed proof sovereigns   
  22. Like
    Elements got a reaction from richatthecroft in Red spotted/finger printed proof sovereigns   
  23. Like
    Elements got a reaction from Miganto in Red spotted/finger printed proof sovereigns   
    After:
    Not perfect but almost all spots removed. With more time maybe I could completely remove them







  24. Like
    Elements got a reaction from richatthecroft in Red spotted/finger printed proof sovereigns   
    After:
    Not perfect but almost all spots removed. With more time maybe I could completely remove them







  25. Like
    Elements reacted to Sovereign in 2005 5 sovereign , NGC PF70 UC   
    2005 £5/5 sovereign 
    NGC PF70 UC 
    stunning coin 
    £1790 posted by special delivery
    UK only 
    Bank transfer please 
    thank you .