"RST Engineering" wrote in
:

I appreciate the information but note that:

a. I cannot send my students/readers down to Home Depot to pick up a
pound of copper chloride along with the muriatic (swimming pool grout
etch) acid.

Send them to HD to get some CuSO4.5H2O [Root killer Zep is one brand] and
some CaCl2 [Damp Rid (or in the winter: ice melter)]

Make a solution of each [equal molar amounts for each chemical] and mix.
Let it sit overnite. The white precipitate is CaSO4 [Plaster of Paris] and
the Blue-green solution on top is the CuCl2 solution. Best to filter that
to remove any remaining CaSO4. Now you have your starting supply of CuCl2
and as you can see from the equations you create more of it as you etch.
If you get too much offer it to another ham to get him/her started.


b. Now I've got a couple of gallons of etchant to keep around the lab
in a proper container for the next go-around.

BTW, what is the color of the CuCl2 and the HCl mixed together?

A very bright green. When it turns a dirty olive green you know it has too
much CuCl so start bubbling air thru until its bright green again.



Jim



"Dr. Grok" wrote in message
news:doqfg.11456$ho6.769@trnddc07...


For etchant I find that CuCl2 and HCl work very nice -- and it is
especially advantagous to agitate by bubbling air thru the solution
since not only does it agitate but the oxygen in the air helps
regenerate the CuCl2 in situ. You can continue to bubble air thru it
after the etching is done to completely regenerate the etchant.

The reactions:
Etching: CuCl2 + Cu - 2CuCl
Regenerating: 4(CuCl) + O2 + 4HCl - 4(CuCl2) + 2(H2O)

Dr. G.