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Unwanted oxidation


#1

Hello all

Can anyone help me with a problem I have. I am quite new to
jewellery making and am still in my first year of nightschool on the
subject. I have made a sterling silver handmade chain, but when I
put it into a vinegar/salt solution for cleaning it turned a dull
dark grey colour. This had happened before in the process when I
put it into Harpic (UK toilet cleaner) to pickle it . I had read on
this site that Harpic is composed mainly of sodium bisulphate but
maybe it has changed its constituents recently? - they are not
stated on the bottle. However, on that occasion I had managed to
restore its shine by putting into proprietary safety pickle (based
on sodium bisulphate), but as it had gone a little dull on wearing I
was trying to brighten it a bit (rather ironic!). To try and
restore it this time I’ve tried the safety pickle and also sulphuric
acid pickle at nightschool, but hardly any of the grey has been
removed. When making the chain, I used borax as a flux for
soldering and coated all silver with borax exposed to the flame of
the torch to prevent firescale.

I did not put any iron into the vinegar/salt solution but it had
been used previously to restore patinated copper and had gone a
bright green colour. I had been experimenting with ammonia /
vinegar/ salt / lemon juice for patination.

Hope someone out there knows what might be the cause and possible
remedy, otherwise I’ll try to rescue it by polishing off the edges
and going for an “antiqued” effect.

Thanks
Margaret O’Brien


#2

You may have used the solutions too strong and etched the metal. I
don’t think of pickling as a way to brighten jewelry. Try a Sunshine
cloth from Rio, water with a little ammonia and a toothbrush, buff
it or put it in a tumbler with shot. I used the salt and vinegar
back in the days when I thought that copper bottomed kitchen pots
and pans needed have the copper shiny. You may have to repolish each
link.

Marilyn Smith