problems with silver oxidation under Reunion Blues leather Valve Guard

Discussion in 'Trumpet Discussion' started by zetka, Sep 17, 2011.

  1. zetka

    zetka New Friend

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    May 15, 2010
    Prague, heart of Europe
    Hello,
    I would like to share my bad experience. About two months ago I have changed my old leather Valve Guard to a new one, made by Reunion Blues, it was not expensive and looking good. Unfortunately I have not take care about one important thing. The older valve guard was made from three layers - leather-plastic foil and something like a felt. The Reunion Blues valve guard has only two layers without the plastic in the middle. I suppose that someting  evaporates from the leather , which leads to fast oxidation of the silver. So this guard seems to be more a silver "damager". I have read somewhere, that some acid tawing chemistry could be a reason...
    The silver I have on my trumpet was done professionally by AMATI, when the trumpet was refurbished few years before. No protection laquer was used. It is stable, I have no problems with oxidation at all on other pars of the trumpet. On the picture you can see, how does the silver look around the valves after about two months of carrying the Reunion Blues...

    Has anybody encountered similar problem?
    Sorry for my English,
    Zetka.
    Pics are few posts below
     

    Attached Files:

    Last edited: Dec 3, 2011
  2. rowuk

    rowuk Moderator Staff Member

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    Zetka,

    silver oxide is not "damaging" like rust with iron is. We can return the silver to its original non oxidized state by bathing the trumpet in hot salt water with a piece of aluminum foil. The oxygen molecules then move from the silver to the aluminum without removing any material.

    If you are really worried about this, then you can use normal plastic wrap from the kitchen to wrap the valves with before adding the leather guard.
     
  3. zetka

    zetka New Friend

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    May 15, 2010
    Prague, heart of Europe
    Thanks for a fast reply. I do not know this clever procedure, can you be more concrete concerning the "hot salt water" - do you mean normal kitchen salt NaCl and which concentration?
    I am worried about that, that one leater guard is not harmful and one is. I can imagine, that after certain time the few tens of micrometers of silver will turn into a black AgO powder...
    Zetka.
     
  4. ComeBackKid

    ComeBackKid Fortissimo User

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    Last edited: Sep 18, 2011
  5. Bob Grier

    Bob Grier Forte User

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    The valve guard you now have is leather and it absorbs the sweat from you hand and holes it against the valve casing. Leather Specialtys make valve guards with a middle layer of thin polymar between the out and inner gaurd. It has a lot of very microscopic holes that keep the sweat out but lets the guard breathe.
     
  6. rowuk

    rowuk Moderator Staff Member

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    Like the reference from ComeBackKid shows, we are using normal NaCl salt. I looked up the chemical reaction and found this from Tania Chase:

    Explanation: Silver tarnishes because it undergoes a chemical reaction with sulfur-containing substances in the air. Silver combines with sulfur to form silver sulfide, which is black, and darkens the silver.The silver can be made shiny again by removing the silver sulfide coating from the surface.

    Two ways to remove the silver sulfide are to: remove it from the surface, or reverse the chemical reaction and turn silver sulfide back into silver. The first method involves polishes that remove some of the silver during polishing. The above demo uses a chemical reaction (which is sped up by heating the water) to convert the silver sulfide back into silver, without removing any silver.

    Aluminum has a lower ionization energy (energy required to remove electrons from an atom of the element) than silver. As a result, aluminum is oxidized (loses electrons and oxidation number increases), and silver is reduced (gains electrons and oxidation number is reduced). Depending on the amount of tarnish, the silver will be bright and the aluminum foil may be brown with tarnish (aluminum oxide), in a short while. The silver tarnish is "transferred" to the aluminum via reactions, which occur instantaneously, as follows:

    3Ag2S(s) + 2Al(s)+ 3H2O(l) => 6Ag(s) + Al2O3(s) + 3H2S(aq)

    silver sulfide + aluminum + water => silver + aluminum oxide + hydrogen sulfide
    (* Note, this reaction can be done without the salt, but it takes longer to see results).

    The important part to know is that no silver is lost, and that the oxidation process does not harm the silver. There is still an issue with acidic sweat that some people have however. This acid CAN eat through the silver (not by oxidation however). Keeping the valve casing dry is beneficial as the acidic sweat is wiped off before it can do much harm.
     
    Last edited: Sep 18, 2011
    gmonady likes this.
  7. zetka

    zetka New Friend

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    Prague, heart of Europe
    I have not used the trumpet so extensively, and the oxidation area equals the touching area of the leather valve guard. I am not sure, if you see the images, to be sure I am adding the link.I am not a very sweeting person, I prefer the feeling of leather against the metal...

    Zetka.

    [​IMG][​IMG]
     
  8. rowuk

    rowuk Moderator Staff Member

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    What we posted is your solution. The black actually comes from sulphur. Perhaps you eat a lot of eggs? In any case, aluminum foil and hot salt water is your solution.


    Chrt pln skvrn vtrhl skrz trs chrp v čtvrť Krč.
     
  9. zetka

    zetka New Friend

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    May 15, 2010
    Prague, heart of Europe
    Concerning the eggs it is negative, but I am able to be poisonous without them. You can see the clear contures of the black the guard on the pics...
    In the meantime the trumpet is in the bath with alumninium but with baking soda, it seems to be too weak, no significant changes. I thought to help to it a little with electric current to make electrolyse to help the ionts to travell..
    Where have you got the crazy czech sentence? More known is "strč prst skrz krk." or there is even a whole fairy tail from Jan Werich without any consonant.

    Where are you from?
    Regards,
    Vojtech.
     
  10. Ed Lee

    Ed Lee Utimate User

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    In addition to the acids in your sweat causing havoc, add to such tannic acid as leaches from the processing of leather. Am I wrong or aren't Reunion Blues products now manufactured in China?
     

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