Homebrew PCBs

Hi Adam-

I have been using the CuCl you helped me to get going over a year ago.
I have not modified the original solution at all, other than by
etching boards. Air is all I use to regenerate.

I use a large vacuum pump as an air source and run it through a
"sparger" (as described at the Think and Tinker website) in the tank.
The solution has continued to etch well, with only the air this method
introduces during board etching. 

The amount of etchant in my tank is roughly 20 litres IIR. Agitation
with this method is quite substantial; the surface is bubbling and
roiling quite energetically. I usually etch small boards, perhaps 3"
by 6" max, and etch times of under 20 minutes at room temperature are
typical.  

The SG, just measured, is 1.262  

Grant
 
--- In Homebrew_PCBs@yahoogroups.com, Adam Seychell <a_seychell@y...>
wrote:
> Anyone here etch with CuCl2 but only rely on air for regeneration ?
Just 
> wondering what other peoples experiences are with this etchant.
> 
> I'm using HCl + CuCl2 at S.G = 1.36 and etch speed appears to be about 
> 70% of fresh FeCl3 (S.G 1.4) at room temperature. The HCl concentration 
> I'm running at is approximately 1N (or 40g/l HCl or 1 Moles/liter or 
> 4%). I found S.G of CuCl2 dramatically effects etch speed. e.g CuCl2 at 
> S.G of 1.15 was about 10 times slower etch speed than at S.G of 1.35.
> Commercially, CuCl2 etchant operates between S.G 1.35 ~ 1.45.
> 
> Adam