Tuesday, November 20, 2012

Dynamic Elements: Copper Patinas


Gold is forever!  Now be honest, don't you think that forever may be a little overrated?  After all forever is an awfully long time!  Gold is praised for its unchanging nature yet monetary value aside, there is something slightly monotonous about gold.  Imagine never changing - being incessantly static!  I find the quality undesirable.

Roman Era Gold Coins (source)

I know I am inconsistent.  Thankfully it isn't just me.  All of us are inconstant and flawed.  So I prefer to wear metals that reflect this: elements like silver and copper that react to the environment and change.  I appreciate that sterling silver darkens over time.  Polish silver and it brightens again.  It serves to remind me that it is attention that renews.

It goes without saying that all preferences are personal.  We each have our explanations for why we are drawn to anything over anything else.  Still I know that I'm not the only one who has ever favoured silver over gold.  Pharaoh Psusennes I, the third king of the twenty-first dynasty of Egypt, was entombed in a solid silver sarcophagus.  His reason for silver over gold?  Simple: in Egypt, silver was scarcer than gold.  You can see that the silver is tarnished and that this tastefully offsets the gold inlaid on the brow.  The old man has aged well.

Silver anthropoid coffin of Psusennes I, Cairo Museum (source: Wikipedia)

Tarnish or patina is a thin coat of corrosion that forms on metals like silver, brass, copper or aluminum.  It is the product of a chemical reaction between the metal and a nonmetal compound like oxygen or sulfur dioxide.  This reaction only affects the first few layers of the metal, unlike rust which will eat right through iron.

Green or blue patinas naturally develop on the surface of copper and brass when the metal is exposed to atmospheric elements, like rain or carbon dioxide. No doubt you have seen the beautiful green domed roofs of old buildings.  These roofs are made of copper which has turned green after years of outdoor exposure to the weather.  Probably the best known example of a patina in the English speaking world is the Statue of Liberty. 

Statue of Liberty's Foot, 2011, photo taken by William Borne

Beautiful patinas can be incorporated into jewelry by distressing the raw copper and brass. To do this a wide range of chemical compounds can be used to force the metal to react and quickly form a patina. The colour is determined by the chemical process used.

 A nice teal patina developed on this copper plate after I sprayed it with salt water and then left in a closed tupperware container with a bowl of ammonia for three days. 

I create my teal patinas by spraying copper with salt water and then exposing the metal to ammonia vapours for days. I use household ammonia cleaner. Since a patina is a surface treatment, it is somewhat fragile, so I seal the finish with a couple of layers of lacquer.

Modernist necklace featuring industrial copper tubing after I applied my patination process to it.

Since ancient times copper has been rumoured to possess incredible healing powers.  Both of my grandmothers used to wear copper bracelets as a remedy for some of their ailments, including arthritis.  So as not to block this healing potential, I do not patina or lacquer the back of the pendants where the copper touches the skin of the wearer.

Copper patina pendants on sterling silver chains.

5 comments:

  1. that is brilliant - thank you for sharing that!

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  2. You are welcome. Thank you for leaving a comment. I appreciate the feedback. :)

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  3. These pieces are gorgeous!

    And I, too, prefer silver over gold. I didn't realize one of the Pharaohs did as well!

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  4. Great and thorough piece on patina! Also, beautiful work on the jewelry!

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  5. Thank you all for your support!

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