Removing Copper Flashing

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Nancy LT Hamilton

Last updated:  12/28/20

Copper Flashing on Brass, Bronze, and Silver

(Not this kind of copper flashing!) Copper flashing has two sources (that I know of).  One source of flashing occurs when Brass (or Bronze) is heated past 850 degrees F.  Zinc (brass alloy) and Tin (Bronze alloy) are more affected by this process than is copper.   Not only is some zinc/tin lost (due to vaporization) during annealing (or soldering) but, more is lost to oxidation.  Zinc oxidizes more than copper so, when pickling, (which removes oxidation) more zinc is removed than copper.  The process is similar to bronze (tin alloy). Got it?  There’ll be a test on Tuesday.

Another method for creating copper flashing on brass, bronze, and silver is to add a piece of steel (containing iron – stainless steel doesn’t work) to a container with jeweler’s pickle.  (Pickle is a dilute solution of acid or metal salts and is used to clean oxides off of metal after soldering). Ever done this?  Put a piece in pickle That you didn’t know had a steel spring in the manufactured clasp?  Or forgotten to remove the binding wire? (Let’s hope you did that only once!) What about using steel tweezers to put a piece in the pickle? Well, congrats!  You’ve created copper flashing.  It’s a very thin layer of copper that is easy to remove BUT can cause dangerous heart palpitations when you see it on your almost finished piece!

Here’s my version of the science behind this mysterious scenario:

If your pickle has seen sterling, copper, brass, bronze, or gold swirling away in its darkened recesses, (you’ll know if it has if your pickle is turquoise!) then there’s copper present. This type of flashing will not work with new pickle or pickle that has only been used with fine silver only because copper is not present in fine silver.

So, when iron is introduced into the pickle, it starts to dissolve.  As it dissolves it becomes ionized.  Basically, that’s a process involving the addition or subtraction of a charged particle from an atom or a molecule. When this ionization occurs, the iron becomes electrically charged.

In our electroplating scenario, the metal salts (or in our case – free-floating copper molecules in our pickle) are positively charged.  The silver or brass are negatively charged and the dissolving iron is the electrical charge. Positive charges are attracted to negative charges so, the copper is attracted to the silver.  As a result of this love affair, the copper engulfs the silver creating a rather stalker-like relationship.  One is left to ponder how the silver feels about all this attention.  Now, of course, since the dissolving iron is only producing a very weak electrical charge, the iron and the silver need to be touching.

To remove copper flashing:

Yeah, she’s finally there!  This mixture is called Super Pickle. Wear gloves and eye protection.  The flashing removal is very fast –  usually less than 5 minutes (generally in a minute).  Don’t leave the piece in too long as it will etch – especially the copper.  Although, I love the matte finish that super pickle leaves on my metal – especially on bronze.  I will mix up a batch of super pickle just for creating this surface finish.  If you leave the mixture out for a day (sans metals), the peroxide will no longer be active (the peroxide converts to water but, the pickle remains acidic). You can pour the pickle right back into the pickle pot.  Keep it away from pets and children as it is still an active acid!

  • If your flashing is caused by a steel/pickle collision, obviously remove, neutralize, and rinse the offending piece of metal. Remove the piece of steel that caused all this trouble.
  • Get out a plastic container – I use Tap Plastics, 16 oz. measuring cups for this job. That way I can measure how much of each I am pouring in.  If the piece is really small, you can just put a tablespoon of each liquid in a smaller container.  I have jewelry dedicated plastic measuring spoons for this and other measuring needs.  They are labeled as such so they don’t get used in the kitchen EVER AGAIN!
  • Mix equal parts regular ‘ole hydrogen peroxide and pickle.  A 50/50 mix works great!
  • Insert piece into the mixture.
  • Wait about a minute.
  • Rinse.
  • Put the panic attack away for now.

Think about this:  what if, someday, you wanted a piece that was coated with copper?  Believe it or not, I have done this intentionally several times.  If I ran out of copper jump rings, say,  and only had brass ones left, I coated the brass ones with copper – that type of thing.  I can’t recall all of the other times but, they did happen – for reals!

  1. Wrap it in binding wire.
  2. Pull some pickle out of the pickle pot.
  3. Put, the pickle,  into a paper or plastic container. Have the pickle deep enough to submerge the piece. Plastic cups work better than bowls because of the submerge ability offered by the deeper volume.
  4. Remove your copper-coated piece.
  5. Boogie to 80’s disco.

You could copperplate/un-copperplate all day.  “It’s coppery – aaah, now it isn’t.  Wow, it’s coppery again – oooh, now it isn’t.  Yippee, now it is.  Well dang me all to hell, now it isn’t.”   I think the disturbing thing is that you are so shocked and awed every time it changes.   I HAVE NOT, actually, spent a day doing this.  I was just imagining how it would feel if you were to do it!