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 the 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 the copper so, when pickling, (which removes oxidation) more zinc is removed than copper. The process is similar with 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 it’s darkened recesses, 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 (no copper anywhere).
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! Wear gloves and eye protection. The flashing removal is very fast – usually less than 5 minutes. Don’t leave the piece in too long as it will etch – especially the copper. If you leave the mixture out for a day (sans metals), the peroxide will no longer be active and you can pour the pickle back into the pickle pot.
- Obviously, remove, neutralize and rinse the offending piece of metal from the pickle pot. 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 in a smaller container. I have jewelry dedicated plastic measuring spoons for this and other measuring needs. Very exciting!
- Mix equal parts regular ‘ole hydrogen peroxide and pickle.
- Insert piece into mixture.
- Wait about a minute.
- Put panic attack away for now.
Think about this: what if, someday, you wanted a piece that was coated with copper?
- Wrap it in binding wire.
- Pull some pickle out of the pickle pot.
- 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 submergability. That IS a new word. I hope.
- Remove your copper coated piece.
- 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!