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Electroclean


#1

G’day - here comes a bit more pedantry: Electrocleaning of
sterling or fine silver is based on the fact that most of the
tarnish is black silver sulphide, which is caused by sulphurin
the atmosphere, or from people’s skins - not much, but it builds
up over time. Removal of the sulphide film can be accomplished
by abrasion (including domestic metal polishes), or by chemical
means. Electrolytic cleaning by immersing the silver into an
alkaline bath with a piece of aluminium in the bottom is one
simple way, though not always effective. Electrolytic cleaning
with an external electrical current works better.

Use a vessel big enough to hold your work, dissolve some
washing soda crystals (sodium carbonate,) - the amount isn’t
important - in hot water in the vessel. (Caustic soda -sold as
Drano in America) is not necessary and only makes the job a bit
hazardous). Connect a wire to a piece of stainless steel; even
an old SS spoon will do, and the other end to the POSITIVE pole
of a car or even a motorbike battery - or a car battery-charger.
Connect another wire to your work to be cleaned, and the other
to the NEGATIVE pole of the battery. The work and the SS
electrode will fizz like mad.

This is where the pedantry begins: The story is that a molecule
of hydrogen gas, consists of two atoms of hydrogen, H2 (the 2
should be in subscript but this don’t work in email!) Now
hydrogen is very reactive and likes nothing better than to join
up with many things, but it needs energy to initiate the
reaction (a little heat for instance).

But monatomic hydrogen H is far more reactive, and when an
electric current is passed through water containing an alkaline
electrolyte like sodium carbonate the energy is used to break
down water into O at the positive pole, and H at the negative,
but they quickly reform to O2 and H2 which dissipate into the
air. However, at the instant of release, the monatomic or
nascent hydrogen, being highly reactive, grabs at the sulphur
film on the work and converts it to hydrogen sulphide (H2S),
which is a gas; the one which makes bad eggs smell bad, though
in this case, there is scarcely enough to notice. Thus the film
disappears.

Oh, by the way, don’t confuse tarnish with the dreaded
fire-stain; they are quite different. And ain’t science
wonderful? Cheers,

    /\
   / /    John Burgess, 
  / /
 / //\    @John_Burgess2
/ / \ \

/ (___)
(_________)


#2

Hi John, It would have been nice if you would have been writing
my chemistry books (zzzzzzzzz) instead of the humorless geeks
from M.I.T. Nice job old son. Jim alpine@hay.net


#3
Use a vessel big enough to hold your work, dissolve some
washing soda crystals (sodium carbonate,) - the amount isn't
important - in hot water in the vessel. (Caustic soda -sold as
Drano in America) is not necessary and only makes the job a bit
hazardous). 

Hi!

How does pickle (I’ve been using Rio-pickle & it says it’s an
acid compound) or Sparex compare to Sodium carbonate or Caustic
soda? Are these two only used with the “Electroclean” method? Am
I confused? :wink:

I have a few pieces that need more than the hand polishing I’ve
been giving them. I have inventory that I rotate in shops one of
which is a Salon—OOOoohhhh, those chemicals they used seem to
tarnish my stuff FAST!! I’ve been very tempted to throw them into
the pickle but haven’t because I’m not sure if that’s safe for
the stones. (Amethysts, crystals, mostly semi-precious stones.)
Will pickle hurt them?

Thanks

Kathie


#4

How does pickle (I’ve been using Rio-pickle & it says it’s an
acid compound) or Sparex compare to Sodium carbonate or Caustic
soda? Are these two only used with the “Electroclean” method? Am
I confused? :wink:

I have a few pieces that need more than the hand polishing I’ve
been giving them. I have inventory that I rotate in shops one of
which is a Salon—OOOoohhhh, those chemicals they used seem to
tarnish my stuff FAST!! I’ve been very tempted to throw them into
the pickle but haven’t because I’m not sure if that’s safe for
the stones. (Amethysts, crystals, mostly semi-precious stones.)
Will pickle hurt them?

The stones that I have personally destroyed by pickling include
a shell cameo, a few pearls and one lapis lazuli, you can learn
from experience. Any chalcedony (agates, jaspers etc) and most
other stones are safe. All the serious stuff- ok. Opals can be
sensitive to temperature changes- likewise certain treated or
filled stones. The gemologists on this forum can probably add
further info, and our resident chemist even more.

Rick
Richard D. Hamilton

Fabricated 14k, 18k, and platinum Jewelry
wax carving, modelmaking, jewelry photography

http://www.rick-hamilton.com
@rick_hamilton


#5

Sorry John, I was really replying to a note that appeared after
yours . … Have a great day! : )


#6

Hi John, being a free thinker, I get the impression that the
"enclosure" (walls built -concrete- to displace the volume of
the tank may be more of a problem than a solution. . . Sheesh,
would I love to have acetylene gas pool into one area of my
basement and maybe cause a bigger explosion than to expand into
the full square footage area of the basement??? I think not.;
Small, more gas in this small area ([perhaps more danger, in my
opinion) Small tank, large floor area, seems like less of a
problem (maybe I’m screwed up, but logically . . . there is no
question.)


#7
   How does pickle (I've been using Rio-pickle & it says it's
an acid compound) or Sparex compare to Sodium carbonate or
Caustic soda? Are these two only used with the "Electroclean"
method? Am I confused? ;-)

G’day, Kathie: Pickle used by jewellers after heating their
work is always acid, and Sparex is a mild acid. It’s use is
mainly to remove flux which is borax based and is an alkali.
Flux would otherwise need abrading to remove it. The pickle also
cleans up other stains, but NOT the dreaded firestain. Only
removal by nitric acid, cyanide de-plating or abrasion will
remove that. Sodium carbonate is a fairly mild alkali and caustic
soda is a very strong alkali - it will harm and corrode flesh.
Only alkalis are used in the electrolytic methods of removing
TARNISH.

  Salons-OOOoohhhh, those chemicals they used seem to tarnish
my stuff FAST!! I've been very tempted to throw them into the
pickle but haven't because I'm not sure if that's safe for the
stones. (Amethysts, crystals, mostly semi-precious stones.) Will
pickle hurt them?

I take it that you mean hairdressing or beauty salons? If so,
I’m not surprised. Both places use chemicals containing sulphur
compounds; hair remover is one, and some mud-packs, hair
colourings, and even a few beauty creams contain chemicals
containing sulphur. I believe it is inevitable that sterling
and fine silver of any kind - be it solid or plated - will be
rapidly tarnished in such environments. Ever watched a good
silver-plated egg spoon tarnish when used to scoop out a boiled
egg? However, I reckon that your pieces will clean up almost
instantly if you used the hand-hot solution of baking soda
(sodium bicarbonate) or washing soda (sodium carbonate) and a
piece of aluminium kitchen foil method mentioned in someone
else’s posting. It is also electrolysis but needs no external
source of electricity. The method I wrote about is only tried as
a last resort.
Don’t try laquers; they look OK for a few days/weeks but soon
wear patchily and look terrible. You may have to think about
only leaving your work in salons for a short periods. Finally,
very few stones will mind being briefly treated in soda
solutions. Don’t confuse pickling with electro cleaning. Cheers,

        /\
       / /    John Burgess, 
      / /
     / //\    @John_Burgess2
    / / \ \
   / (___) \
  (_________)