Hi Folks, Does anyone have a formula that will color or darken copper
but not effect sterling silver? How about copper and fine silver?
Thanks, MP
Hello Michael,
You can use Calcium sulfate in cold (max 5 degrees Celsius) water.
(approx. 1 gram in a cup of water) This affects the copper more than
the silver. If the water is hotter also the silver will be dark. You
can add some ammonia (tee spoon) to the solution to get a more blue in
the patina. If you do not succeed than there is the mechanical way to
clean the silver. The copper oxide is harder than the silver oxide, so
if you are using some soft brush and white (pumisch, chalk) polish,
you can clean the silver without damaging the copper patina.
success,
martin Niemeijer
I use Baldwin’s Patina from Reactive Metal Studios. Turns the copper
the color of an old penny, and leaves the silver unmolested. What I
really like to do, though, is flux my whole piece well for the final
soldering, let it air cool for 30 seconds to a minute after the solder
flows, and then throw the piece in water rather than pickle. This
turns the copper a durable red, somewhere between cherry and
burgundy. I can polish the piece with Zam or Fabuluster without losing
the patina. In fact, the patina becomes deep and glossy with
polishing and could almost be mistaken for enamel.
Lee Einer
Hello Michael, Use just a bit of heat. The copper will darken and
leave the other metals alone. Have fun. Tom Arnold