On 29/07/13 02:01,
kabowers@... wrote:
> This is often considered the best writeup on the subject.
> He mentions starting with HCl, Cu, and H2O2, but I've never
> found a copy where he completed that section
> He does cover starting with HCl, Cu and air.
>
> href="http://techref.massmind.org/techref/pcb/etch/CuCl2.htm"
Ah. Looks like I should expect a ~10 day wait then.
I have managed to get my hands on 200ml of 9% H2O2 ("look, that's all I
can sell you, the law says so"), though I'm not convinced this will be
enough to start a 1-litre tank.
A quick scan through one of my old threads (from 2010, yeesh!) suggests
the mix ratio for 9% H2O2 / 17.5% HCl should be around 2 parts acid to
one peroxide. That gives me (2x200)+200 = 600ml of etchant, all being well.
I've got a few small boards to start with - I'll probably chuck in some
(stripped) scrap copper wire I have lying around, then the peroxide,
then the acid ("add acid to water"), give it an hour and maybe chuck in
the PCB.
That said, I suspect my heavily used FeCl3 bath is mostly CuCl2 at this
point. After getting rid of the precipitates a few months ago and adding
what I'd describe as "way too much" HCl, it turned green with a hint of
brown to betray its iron content. Very strange stuff and very prone to
foaming if the air pump is turned up to full...
--
Phil.
ygroups@...http://www.philpem.me.uk/