To Oxidize or Not to Oxidize

by Judy Ellis, Wirejewelry.com

WireJewelry Article for November 2nd, 2015

To Oxidize or not to Oxidize

by Dawn Horner ©2015

To Oxidize or Not to Oxidize, what’s it all about?

When deciding what materials to use when designing, solid (non-plated) metals can provide extra options that plated/colored types don’t.   Although colored metals do have the benefit of bringing variety into your work to compliment or contrast with other elements like stones, beads and crystals.  As a wire worker, I never initially had the exposure to “colorways” that bead workers did, so I used online free “color wheels” to learn about the different families of colors I could pull into my work.

Fixing Dings:

But even the steadiest hands loose their grip and slip scratching a tool against a new design and leaving unintended marks on the metal.  These marks can scratch off the shiny non-tarnish coating or color from coated wire and the exposed area is prone to natural tarnishing later.  This results in a shiny non-tarnished design that looks like it had pepper spilled on it.  It can be a good idea to keep imperfect practice pieces around to see how they behave months later when left out and treated like your customer’s might care for them so you can see the whole picture.

To deal with markings on plated/colored wire, prevention is key.   Scratches or pressure marks can be minimized by coating tool tips with a buffer-coating like Tool Magic or other plastic dip-type coating which peels off easily after use.  Also, developing intuition over time for how much tool and hand pressure is needed helps, too.  When learning a new skill, it’s instinctive to grip a little tighter and tense the upper body until fine motor muscles find their flow and ease up a bit.

Go with the Flow and the Power of Oxygen:

Using non-plated, solid base metals opens the door to a few other options.  Tool marks and scratches on the metal surface can be sanded away using files, sanding sticks or sanding sponges.  The filing action removes tiny amounts of surface metal which is why it’s useful only on solid metals.  To get a smooth result, work from from coarser to finer grits on the area to remove the mark then gradually smooth the new surface.

Many metals will oxidize or experience surface changes over time as a result of being in contact with oxygen.  Oxygen is in air and in water and acids.  Think about sweat and how exercise or living in a hot environment causes jewelry to tarnish or oxidize faster than desired.  (Body sweat is 4.5 – 7.0 Ph, so it’s on the acidic side.)  It also explains why something as simple as keeping jewelry in a zip-lock bag can prevent some oxidization by decreasing exposure to oxygen.  Though eventually the jewelry must come out to be enjoyed, so decide whether to attempt to prevent or push the natural oxidization as part of your designing.

Some people seek to seal their designs using waxes or spray clear acrylics.  These will act like a clear nail polish coating, and may be prone to yellowing and drying out depending on the quality used.  Stones and other components in the design also might not be happy being coated by the acrylic.  For those who desire to keep their metals shiny,  a great article on cleaning copper and brass, can be found HERE.

Push the oxidization:

Using agents to force the color change instead of waiting for oxidization to take place naturally is an option.  This also avoids having to watch a piece oxidize slowly which can have it’s unattractive moments and customers may not understand the process.  Many people have commented to me that they don’t like silver jewelry specifically because it looks “dirty” to them.   When silver tarnishes it goes through a process much like dying hair darker as it goes blonde, then coppery then black.  They’re noticing the first phase of the brassy change and they assume the jewelry is dirty.   When jewelry is fully darkened and re-polished, those unattractive phases are avoided, and the pieces just need worn frequently to keep the high points buffed off.

There are a variety of patina methods available and some are dependent on the metal type  being treated.  My favorite for sterling and copper is  Liver of Sulfur (LOS), which is a  potassium sulfide.  It works on copper alloys, which includes sterling since it contains about 7.5 %  copper to help strengthen it.  Brass is not as reactive to LOS and may require different chemicals to get a good patina.  There’s a big conversation that Liver of Sulfur doesn’t actually oxidize metal, but the darkened result serves us well without having an advanced scientific discussion here.  One thing not up for debate is that LOS has a characteristic stinky rotten-egg smell.  It’s similar to the smell noticed at natural Hot Spring pools, and those will have the same effect on jewelry if it’s worn swimming there.

When used in the rock lump form, Liver of Sulfur can have an unstable shelf-life and weaken quickly over time.  Currently there are stabilized gel forms that require just a small amount for the desired result, so the first bottle goes a long way!

Steps to use Liver of Sulfur:

1. Liver of Sulfur should never be added to an acid or be boiled.  The most likely acid in your work area could be pickle solution if you do work in soldering.  Mixing LOS with an acid or boiling it creates a harmful gas, so those are NO-NO’s!  This is important since designers often use crock pots to heat both pickle and LOS when used, but the two should be assigned their own pots for safety’s sake.
2. To prepare:  Mix a diluted solution by using an old plastic food storage container.  Fill with enough hot (not boiling) water to cover the piece being treated.  Add a small amount (i.e. 1/8th –1/4 tsp) and stir with a plastic utensil reserved for LOS work.  Add your design and stir it around until black. Copper may turn rapidly, but sterling might take 30 seconds to a minute or two.
3. The speed of the change depends on heat and concentration: the heat of the solution, the heat of the piece and the strength of the solution mixed.  The jewelry can be he held under running hot water to heat it up before placing it in the prepared solution.  Or the solution can be mixed in water heated in  a small crock pot reserved for LOS work.  This can be helpful when treating multiple pieces in one session preventing the solution from cooling.
4. Remove the piece and rinse it off under cool running water and scrub with a 0000 Fine steel wool pad to clean off the high points.  Use an old toothbrush with Dawn dish washing liquid to scrub out the little bits of steel wool from the wire and proceed to polishing it with a polishing pad, sunshine cloth or rotary tumbler.
5. Plants benefit from Liver of Sulfur, too!  After use let the solution sit in a plastic container in a safe place until it turns milky white, then it’s neutralized and safe to water plants with.   I credit old LOS water for keeping my plants alive during our winter days with only 5 hours of light in the Alaskan winter.

Here are two before and after pictures of rings in copper showing shiny versus patina/darkening with Liver of Sulfur.  Regardless of what finish you find the most appealing, experiment and be informed about it so you can educate your friends and customers in what to expect from their pieces.

 

 

Disclaimer: this article is a result of my experience and research during my jewelry designing and is only an introduction into the concepts discussed.  The reader is encouraged to engage in learning as part of their own artistic practice before engaging in the use of new materials and tools. 

I hope that you’ve enjoyed this great article from Dawn.  I know that I have!

Happy Wrapping!

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7 Comments

1. 

   Cheryl

   November 2, 2015 at 6:24 am

   I absolutely like the one with the patina better.
2. 

   Sharon Wyman-Rogers

   November 2, 2015 at 6:57 am

   Great information for those of us just venturing into the world of oxidization. Thank you!
3. 

   Kat

   November 2, 2015 at 7:23 am

   T.Y. I look forward “To All Your Tips”.
4. 

   Dawn

   November 3, 2015 at 2:35 am

   Thank you ladies for your feedback!
   -Dawn
5. 

   Emilie

   November 9, 2015 at 10:10 am

   Great job,,, love the patina….
   your site is also, wonderful…..
6. 

   Beth

   November 9, 2015 at 3:16 pm

   This article was very helpful. Wondering if liver of sulpher will colour stones that are already fixed in the jewellery piece & dipped eg light brown patterned jasper.

   Would also love to have some tips about the types of sealants that can be used on copper wire.
7. 

   Ellen Johannessen

   November 9, 2015 at 4:09 pm

   Pleas, can you tell me what wire is best for viking nitting, will 20 gorge be ok. or should I use thinner. Can I use Argentium wire??
   Is it possible to oxidize Argentium?