Thursday 19 February 2009

Oxidization - giving your silver an antique effect

After the tutorial I wrote about cleaning silver I had a couple of requests to show people how to do the exact opposite - deliberately tarnish (oxidize) silver! So, here is the first of two tutorials - this one uses a chemical, Liver of Sulphur (LoS), that many jewellery suppliers and art clay suppliers stock to give silver antiqued patina. The second, coming later this week, uses a common kitchen ingredient - more on that later!

Although to those of you who haven't done it before deliberately oxidizing your work sounds like a very strange thing to do, it can enhance the beauty of many pieces of work, especially those with a texture. The pieces of jewellery in this tutorial have been oxidised and then have had most of the oxidization polished off, leaving the crevices of the pattern darker and therefore more obvious. Oxidizing silver and then polishing most of the oxidisation off is also a way of making the silver less obviously bright, a look that I've found is popular on men's jewellery.

A couple of things to be aware of:
  • You can use hot, warm or cold water in this method - obviously don't use hot water if you are oxidizing a piece with glass beads in, especially lampwork beads, as they can break under extremes of temperatures.
  • Oxidizing items with pearls using LoS can harm their delicate surface, so if you want to oxidize pearl items wait until the next tutorial later this week!
  • LoS is smelly! Store it on an air tight container.
  • Obviously don't use a container that you want to use for food later on.
  • LoS needs to be stored away from daylight or it will lose it's potency.
  • Don't clean oxidized silver using the bicarb of soda method or with silver dips as you will clean the oxidization away!
  • The liquid LoS that I use is mild liquid solution that is harmless if you get it on your skin (well, harmless apart from the smell that might linger, that is!). The solid form that is sold in the UK is usually potassium polysulphide which is mildly corrosive - make sure that you read and follow the safety precautions that come with the LoS that you buy.
So, you will need:
  • A container big enough to easily hold the piece(s) you wish to oxidize and enough water to cover them - I prefer to use clear glass containers as the water I use is hot, and I can see my work better through the glass
  • Hot water
  • Soap
  • Clean water for afterwards
  • A soft cloth to dry your piece
  • A polishing cloth
  • A fine sanding pad (optional)
  • Liver of sulphur - I use the liquid form, but it also comes in a solid form that dissolves in water (for stockists see end of post)
  • And obviously the piece you wish to oxidize!
What to do:

  1. Wash the piece(s) you wish to oxidize with soapy water to get rid of any traces of oil and dirt as this will prevent the oxidization process from occurring. I forgot to do this once and ended up with a thumb print that wasn't oxidized on the back of a pendant! I had to remove the oxidization and start again. I don't really need to show you a picture of washing the jewellery do I? I'll show you a lovely picture of some earrings instead - one pair of which have obviously been oxidized!
  2. Fill your glass container with enough water to cover your piece(s) of jewellry - the hotter the water, the quicker the process. I use very hot water from the tap or just boiled water from the kettle. The process will still work with cold water but it will take much longer. You can also heat your piece by rinsing it in hot water too.
  3. Drop a couple of drops of LoS into the water...
  4. ...and mix it in - I use a wooden chop stick or lolly pop stick.
  5. Drop your piece into the LoS. If possible hook your piece onto a length of scrap copper wire so that you can easily pull it out again. This also makes it easier to stir the jewellery in the solution to speed up the process and help make sure that the oxidization is even.
  6. Keep checking how much the piece has been oxidized.
  7. Once the colour is what you want rinse it in clean cold water to stop the oxidization from continuing. It is possible to get a range of bluey/greeny/purply colours on silver using LoS - the colour depends on how long you leave the piece of silver in the solution and how hot the solution is. I prefer to let my piece go very dark and then polish most of the oxidization off. Some people prefer the colours, others still use colder water and leave the silver in for a very long time to go almost black.
  8. To remove the oxidization from the top of the texture use a polishing cloth. You can also use use a fine sanding pad to speed the process up, and then use the polishing cloth afterwards - mind any stones or beads if you use a sanding pad though. Assuming the piece of jewellery doesn't contain stones/beads that can't go in a tumbler, I also use a tumbler to give a final polish that also helps to make the oxidization much longer lasting. Oxidization won't be completely removed from a piece, but areas of oxidized jewellery that are rubbed frequently (ear wires for example) may become lighter in colour.

If you change your mind about the oxidization or, like me that time with the pendant you've realised that you didn't clean your piece of jewellery properly at the start, there are a couple of things that you can do:
  • use the bicarb of soda method of cleaning silver that I wrote about here.
  • Heat the silver up with a blow torch (assuming that it doesn't contain any stones or beads). Remember that you will have to quench and pickle the piece afterwards.
  • Use a silver cleaning solution.
Stockists:
I hope that you have fun with this! Do let me know how you get on, or if you have any tips of your own.

3 comments:

  1. Hi there
    I love your blog and wonder whether you would be able to show how you cut out your jewellery shapes, eg the daisies, that make your lovely pendants. Do you use special scissors?
    It's really interesting! Thank you.

    ReplyDelete
  2. Thanks for the compliment! I saw the shapes out of silver - I'll see if T can take some photos of me in action!

    ReplyDelete
  3. what great tutorials! I really like this one as it clearly explains the steps in using the liver of sulfer. A question... what exactly is the 'ingredients' in pickle? I'd like to start doing this but don't know what i need for the pickle.

    ReplyDelete

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