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/ > > >
Message
RE: Re: CuCl etchant - an update
2013-09-03 by <twgray2007@...>