Homebrew PCBs

I have a question about CuCl etchant.  I mixed up a galon of the stuff using the standard off the pharmacy shelf H2O2 and HCl I normally use in my swimming pool.  It worked great in my etchant tank the first time, but I have been unable to get it working again.  I've added more H2O2 and HCl but to no avail.  The liquid is a nice transparent lime green.  Any suggestions on how to recharge the stuff?


--- In Homebrew_PCBs@yahoogroups.com, Philip Pemberton <ygroups@...> wrote:
>
> 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/
>