dkesterline wrote:
>
> I tried this and my results were less than stellar. The negative
> terminal collected particulate copper (kinda looked like a sponge,
> but just dust, wiped off easily) and the negative terminal did erode
> some (about 1 hour). In the end my etchant looked like brown mud.
> Then I tried etching with it and it seemed slower than before I did
> it.
If you have potential too high then your change all your ions.
I.e. you get hydrogen ions (+1 charge) and copper ions (+2
charge) attracted to the negative terminal because that's where
electrons are being feed. Simultaneous deposition of hydrogen gas
and copper metal make you a messy sponge.
Lower the cell potential so hydrogen no longer evolves and you
get only copper.
On the opposite side your anode will attract negative ions
(anions) i.e. chloride (-1 charge) and hydroxide (-1 charge).
But you have iron anode material, and electrons are being sucked
away from the surface. The result is iron becomes iron ions (+3
or +2 charge). The chloride ions don't get a chance to give up
their electrons because the iron does it so much easier. The
hydroxide may do it a little bit and so you might get some oxygen
gas evolving.
Electrochemistry is a nightmare to understand.
I wouln't expect results, at best you can plate out all the
copper and finish up with saturated ferrious chloride solution.
Adam