Right then, time for a quick update...
My CuCl etching bath seems to be well on its way. As of last night, it
was dark green in colour with white foam and looked like it had oxidised
as much as it was going to. I added the last few bits of copper wire
(which were left over from the startup attempt) and turned the air
bubbler back on.
This evening I found the liquid in the tank was completely opaque -
white with a hint of green. Almost like someone had dumped a bag of
plaster mix in there... Oh dear. This one isn't in the manual...
I don't have a hydrometer, so I can't check the specific gravity of the
solution. For bonus points, I'm still trying to track down some suitable
containers to do the titration test Adam Seychell describes on his webpage.
... However the photos of the "you've added far too much NaOH" titration
looked oddly like the contents of my HCl+CuCl tank... which got me
wondering -- was the tank low on acid?
Turns out it was. I added a bit of acid (by the highly unscientific
"just add some with the bubbler on until it's not cloudy any more"
method) and the cloudiness vanished, leaving the green-black liquid I
had before.
It's now back on the air bubbler (and foaming like crazy), though given
the colour of the solution I think it may have already oxidised as it's
going to (although it went a heck of a lot brighter when I last threw in
some peroxide, though I'm all out of that at the moment).
--
Phil.
ygroups@...http://www.philpem.me.uk/