Etching and ammonia

I can't imagine why any one would even dream about etching copper
with ether stronger (28%) ammonia, a standard industrial water
solution or anhydrous (100%) liquid ammonia. 
neither is friendly a material !! copper does react with ammonia 

While you are right about it not being a very friendly material it
was used at Hewlett Packard in Colorado Springs for etching printed
circuits in the early 70’s. We had a machine that was filled with
the high strength ammonium hydroxide. The circuit boards were run
through it on a stainless mesh belt the solution was sprayed on the
boards and there were a series of rotating brushes that scrubbed the
boards as they proceeded through the machine. The copper was
completely removed from the boards in a matter of a couple of
minutes. The only metal remaining after passing through the machine
was where the traces had been plated with gold which acted as a
resist to the ammonia.

James Binnion
James Binnion Metal Arts

Cyndy,

I just use the stuff from the drug store, 3%. Use it straight, with
a little used pickle, or fresh granules, sodium bisulfate. It’s very
seat of the pants, but keep your eye on it, and experiment. It can
cut deeply.

The very best part is when you slip up and pickle a silver charm
bracelet with steel and the copper plates out all over the bracelet,
just put it in the solution and watch the copper magically
disappear. Don’t make up any more than you are going to use. It
doesn’t keep.

Tim

Ok, just read this to my husband, a metallurgist chemist. Silver
dissolved in ammonia, upon drying will form silver nitride which is
an unstable contact explosive. So don’t let the solution dry out,
even at the edge of the pot. because it is very unstable. He agrees,
cuts well. but explosive issues.

Jo Dean

Ok, just read this to my husband, a metallurgist chemist. Silver
dissolved in ammonia, upon drying will form silver nitride which
is an unstable contact explosive. So don't let the solution dry
out, even at the edge of the pot. because it is very unstable. He
agrees, cuts well. but explosive issues. 

There may be a little misunderstanding here. Ammonia is used to etch
copper not silver. While there are several silver compounds that are
highly unstable (explosive) it takes a little more complicated
process to produce them than putting metallic silver in ammonia to
end up with silver nitride. Silver compounds (silver nitrate, silver
chloride. etc) are a different story and unless you know what you
are doing do not mix them with other chemicals.

James Binnion
James Binnion Metal Arts

You are correct, i thought of silver etching when I read the
article. Copper is not a problem. Thanks for the I am an
enamelist and wanted to try etching. This sound promising.

Jo Dean Sarins
Array of Elegance