[Jewelry making - Article 00918] - [Orchid] Tarnish remover use aluminium foil

[John Burgess]

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G'day.

    There is no secret in this process of tarnish removal. The tarnish on
    silver items is nearly always due to sulphur combining with the
    surface of the silver, whether from atmosphere, body oils, or
    patinating compounds like the polysulphides. 

    Aluminium foil is attacked by alkalies, like sodium carbonate or
    bicarbonate, with the result that pure 'nascent' hydrogen gas is
    given off. Normally hydrogen nearly always goes around intimately
    associated with another hydrogen atom, and is written H2. But when
    freshly prepared by this reaction, the hydrogen is just single atoms,
    though it quickly pairs with another H atom. So the fresh highly
    reactive hydrogen reacts with the sulphide molecule of the tarnish to
    produce minute quantities of hydrogen sulphide gas, which bubbles
    off, leaving pure silver. Thus the surface will look slightly rough,
    but can easily be burnished to a bright finish. You will see that no
    silver is removed in this treatment. 

Cheers for now,
John Burgess; johnb AT ts.co.nz of Mapua, Nelson NZ

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