Homebrew PCBs

On Tue, 06 Sep 2005 05:46:55 +0200, Adam Seychell  
<a_seychell@...> wrote:

> Dull green is ok, only when it becomes brown is the problem. If you
> dilute a bit of it and it turns bright green then its pretty much
> regenerated. But, this doesn't necessarily mean it'll etch ok.
> I here a lot of people on this group that cannot get air re-generated
> cupric chloride to work, simply because they run their solutions too
> damn week. I have done a side by side comparison with fresh full
> strength ferric chloride (sp.gr 1.47), under exact same conditions and
> the cupric chloride (without any H2O2, ever) is only fractionally slower
> (7.5 minutes for FeCl and 9 minutes for CuCl for bubble etching, 35um
> thick copper at 15\ufffdC).
> Adam


i agree, you need a strong solution to do air-regeneration.
For H2O2, anything works, but as it grows denser the time between H2O2  
applications can be extended, wile at the beginning with a very weak  
solution you need to add it each time you etch, at least. Density, and a  
enough volume, are the key to air regeneration i think.


ST