?

Log in

No account? Create an account

in a web of glass, pinned to the edges of vision

Today, a useful discovery, yay!

I'd forgotten how often we saw Magritte

mucha mosaic

Today, a useful discovery, yay!

Previous Entry Share Next Entry
mucha mosaic
Baking soda, hot water, and aluminum will remove tarnish from silver without the faintest application of elbow grease.

Which is useful for, in this case, a fragile silver pendant I had thought to have been lost for good, and had missed very greatly.


How it works:
The aluminum produces ionized particles when heated up with the baking soda.
The aluminum ionized particles bond with the crap that's bound to the silver, much more readily than it binds to the silver.
What you use: just a sheet of aluminum foil in the bottom of a pot; sprinkle on the baking soda. heat water, insert silver, remove silver.
You can just use Very Hot Water from the tap; it takes longer (just soak it for a half-hour). The boiling method is nigh-instantaneous.
Result: a pot full of undrinkable water, and SHININGLY clean silver.
This data brought to me by sinick, who also supplied a kid's science experiement which explains things. PDF file, in case you are a person who objects to such.
  • What do you do with the aluminum? Is it just dissolved in the baking soda solution? And if so, in what form? Or are we talking aluminum foil here, and if so, how is it applied?

    I've got a bunch of silver earrings I need to clean...
    • Details for the detail oriented:

      How it works:
      The aluminum produces ionized particles when heated up with the baking soda.
      The aluminum ionized particles bond with the crap that's bound to the silver, much more readily than it binds to the silver.
      What you use: just a sheet of aluminum foil in the bottom of a pot; sprinkle on the baking soda. heat water, insert silver, remove silver.
      You can just use Very Hot Water from the tap; it takes longer (just soak it overnight). The boiling method is nigh-instantaneous.
      Result: a pot full of undrinkable water, and SHININGLY clean silver.
      • Re: Details for the detail oriented:

        Ah. Thanks.
        • Re: Details for the detail oriented:

          The aluminium foil goes very dark and manky because it's picking up all the sulphur compounds that used to make up the tarnish layer on the silver. If it's used to clean up enough silver items (say the family silver service) the aluminium foil will actually crumble to bits.

          The really great part of the electrolytic method is it's the only way to clean silver that actually leaves you with the original amount of silver you had before it was ever tarnished. All the other methods of cleaning silver (cloths, pastes etc.) work by physically scrubbing off the tarnish layer, which of course means you lose silver, and in the case of sculpted/figured items, abrade the surface details irreversibly.

          I'm thrilled you liked the little recipe! Times like this it's nice to be a chem geek / jewellery/lapidary freak.
  • You must tell me how the aluminum comes into it. I knew baking soda could work miracles on many things, but never thought to use it on silver, for some dumbass reason having to do with my obesssive intention to buy some silver polish one of these decades.

    Good new icon.
    • More details

      How it works:
      The aluminum produces ionized particles when heated up with the baking soda.
      The aluminum ionized particles bond with the crap that's bound to the silver, much more readily than it binds to the silver.
      What you use: just a sheet of aluminum foil in the bottom of a pot; sprinkle on the baking soda. heat water, insert silver, remove silver.
      You can just use Very Hot Water from the tap; it takes longer (just soak it for a half-hour or so). The boiling method is nigh-instantaneous.
      Result: a pot full of undrinkable water, and SHININGLY clean silver.
  • Thank you! This is a very helpful thing. Been rooting through the jewelry collection lately, and lamenting the state of many things.
    • boiling water is preferable for rapidity of cleaning, I am given to understand.
  • Aluminum + silver + electrolyte makes a battery, right? And that electromotive force knocks the tarnish (silver sulfide and such) right off into the basic solution.

    Mind you don't leave your pendant in there too long; it'll go the way of all good electrodes and dissolve.
    • Yep. It's already out- just soaked it for about 1/2 hour in warm water+ baking soda.
      The silver will eventually bond to the aluminum if you do this too long, yes: the first thing to bond, though, is the non-silver portion of the compound that is tarnished silver.
      • True. As with every oxidation/reduction reaction that involves valuables, don't leave it unattended. Take out the silver as soon as it's clean and rinse it _thoroughly_.

        To help prevent tarnish recurring:
        Don't store silver near materials that exude sulphur or salt (latex, natural tortoiseshell etc). Unfortunately, skin is pretty bad for both these compounds.

        Best stored in a dark place, in an airtight bag with the air sucked out. If you're extra picky/determined to keep tarnish at bay, add a sachet of activated charcoal into the airtight bag (you can get it from aquarium suppliers: they use it for tank filters). The charcoal absorbs sulphur compounds, but it won't work indefinitely of course. Change the sachet annually.
  • Eureka!

    I've always used a baking soda and water solution to polish my silver gewgaws, but always with a wearying amount of scrubbing. My joints rejoice at this new bit of knowledge.
  • Long live red-ox chemistry!

    Mostly sulfides and chlorides and perhaps nitrates, I imagine, are what you're getting rid of. AgCl (Silver Chloride) is largely insoluble in water and definitely is the right color. AgNO3 (silver nitrate) also has the right look about it, though it's much more soluble in water.

    As for the use of hot water, it's simple kinetics. It just makes the red-ox reaction (Al -> Al 3+ while Ag+ -> Ag) go scads faster.

    The bicarbonate (HCO3-, or baking soda) isn't actually the cleaning agent in this case, either (though in many, it is). Bicarbonate is a very common catalyst for aqueous electrolysis reactions (water being split into hydrogen and oxygen is made 1000-fold faster with some bicarbonate in the water, for example).

    Chem-geeking... It's been a while.
    • Exactly right, though tarnish is silver sulphide. Baking soda not only catalyses the reaction, making it go much faster, it also makes for MUCH more pleasant gaseous byproducts.

      The core reaction is:
      3 Ag2S(s) + 2 Al(s)+ 3 H2O(l) -> 6 Ag(s) + Al2O3(s) + 3 H2S(aq)
      (silver sulphide + aluminium + water -> silver + aluminium oxide aka bauxite + hydrogen sulphide aka rotten egg gas)

      Fortunately, the baking soda reacts with the rotten egg gas, producing nice odorless nontoxic carbon dioxide.

      3 NaHCO3(aq) + 3 H2S(aq) -> 3 NaHS(aq)+3 H2O(l)+ 3 CO2(g)
      (baking soda + rotten egg gas -> sodium hydrosulphide + water + carbon dioxide)
  • (no subject) -
    • It didn't damage the quartz, ceramic, or garnet of which this piece was composed. What manner of semi-precious gems are you thinking of?
      • (no subject) -
        • Be very very careful with labradorite. Like opal, it's a fragile and finicky stone, and for the same reason: its iridescence is the result of microfractures. Dealers often store it in water or glycerine like opal, to prevent the stonefrom drying out.

          Personally, I'd _not_ recommend this method with stones like opals or other microfractured/hydrated stones, stones with large flaws (surface fissures visible to the naked eye), inclusive stones such as rutilated quartz, and with organic gemstones (pearl, coral, amber, jet).
  • Very cool. Thanks for passing this along, Colubra. Cute icon, btw.
    • You're very welcome! And the icon was drawn in Boy Meets Boy, the only webcomic I read regularly (and whose artist occasionally comments in my LJ). I had noticed I needed a happy icon, and I thought the character looked far too happy in that pic.
Powered by LiveJournal.com