A science lesson for an old charmer


The new-style charm bracelets have dominated the market for several years now; I'm talking about the likes of Pandora, Trollbeads and Charmilla. They are brilliant for chopping and changing the colours or collection you want to wear.

There is something slightly less practical, but possibly still more charming (pun intended!), about old-fashioned sterling silver charm bracelets. My sisters and I had one each when we were younger. New charms were added by a jeweller, who usually attached with a jump ring and then soldered it closed. They have a beautiful vintage look and a gentle, "tinkly" musical sound that cannot be beaten by those round glass beads...

I cleaned mine up after years of it sitting in mum's jewellery drawer. It came up so nicely that I recently got hold of my sister's, to do the same for her. I'm sharing the (surprisingly easy!) process here.


You can see this silver has oxidised considerably over the years. When silver oxidises, it actually combines with sulphur to form a compound that gives that dark colour to the surface. You might choose to keep a piece this way, with a more antique look. 

But if you do want to clean it up, you can see that there is no way to get into all these nooks and crannies with a polishing cloth... These old-fashioned silver charms have so much detail! 

  


Gather a few tools...

You don't need to be a pro to put some shine back into a piece like this, but it's handy to be able to make minor repairs or changes before you clean up the piece.


Small wire cutters can be useful if you do decide you want to move or remove an old charm that has been soldered on - they will usually cut through the jump ring at the solder point quiet easily, as silver is fairly soft.

The jump ring opener is a fairly new tool for me, but makes it much easier to twist open jump rings vs. holding on to each side with a different set of pliers!

If this is your first venture into jewellery manipulation, there are some great, simple guides at Kernowcraft. For example, see their clear photos of how to properly open and close a jump ring with a twisting, not pulling, action...

The original clasp on this bracelet was the beautiful little heart-shaped faux lock you see in the top photo. Unfortunately, this mechanism no longer holds shut. I decided I could move this and use it as a charm, adding a modern clasp to restore function. The little safety chain is in tact and still useful.

Give it a basic clean

Start with a gentle clean with some diluted fairy liquid, to remove any greasy residues on the jewellery. You can use a clean, unused make-up brush to get into small corners!


Make up your silver "dip"

This is where science gives us a wonderfully simple clean-up method.

I suggest you only try this on jewellery that you know is sterling silver and that is not completely irreplaceable! Accidentally having other materials in the mix might lead to weird and wonderful things happening...


1-  Line a clean bowl with a piece of clean aluminium foil.
2-  Add a teaspoon of salt and a teaspoon of baking soda.
3-  Add hot (but not boiling) water on top and let the fizzing settle down a bit!
4-  Open up any moving parts or charms on the jewllery, so that the liquid can get inside easily.
5-  Lay your jewellery in the salt bath, sitting on top of the foil.
6-  After about 15 minutes, remove the jewellery. Wash well with a further dab of fairy liquid and then rinse in clean warm water.
7- Dry with some clean kitchen towel and then leave out overnight on a clean, absorbent tea towel, to allow any residual moisture to dry. Never put jewellery away damp.
8-  Give a final polish to surfaces with a silver cloth and admire the new sparkle!

 Town Talk Polishing Cloths


The Science

There is some very simple science behind this process, that takes all that dark, silver sulfide away with so little effort! The geek in me finds it secretly a bit fascinating...

The basis for this reaction is that where any one thing is being oxidised, another one must be being reduced. These two reactions come as a pair! 

The direction of the reactions is driven by the most reactive metal. This means you can make use of something you keep in your kitchen cupboard, because aluminium is more reactive than silver! So in this mixture, Aluminium "wins" in terms of reactivity and gets to to oxidise:


This drives the reverse reaction on for the silver sulfide on the surface of your jewellery, which is forced to reduce:


The net effect is a shiny silver bracelet and a slightly sulphurous "eggy" smell as (harmless) hydrogen sulphide is let off!


You just can't get this kind of result from a polishing cloth alone:






2 comments:

  1. I bought a $20-kit some years ago, that was a heavy aluminum sheet to put in the bottom of the sink. Directions said to add "washing powder." It worked great, but if I had known the science behind it as you describe, it would have saved money. I LOVE your solution to silver-cleaning, and when you're finished, you toss the solution and foil--no trying to remember where you stored your aluminum plate kit. Thank you for this valuable tip!

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