Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

previous by date index next by date
previous in topic topic list next in topic

Subject: RE: Re: CuCl etchant - an update

From: <twgray2007@...>
Date: 2013-09-04

Well mine is bright emerald and completely transparent...and not etching.
 

--- In Homebrew_PCBs@yahoogroups.com, <homebrew_pcbs@yahoogroups.com> wrote:

Refresher.

Small amount of Hydrogen peroxide.(optional)

Drop in a small piece pf copper and bubble away.

your looking for a dark green color.



This is an excellent write up... the best imho.

http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/













--- In Homebrew_PCBs@yahoogroups.com , "Terry" <twgray2007@...> wrote:

>

> 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/

> >

>