Homebrew PCBs

Stefan Trethan wrote:

> 
> Of course, more CuCl means more etching, i guess it is the same with any  
> etchant.

All references I've seen for hobby etching with CuCl2 is S.G < 1.2, 
which in my experience found to be almost useless as an etchant.  If 
H2O2 is present then etching rate is fast regardless of S.G even with no 
CuCl2 present! It seems the etch rate is very sensitive to CuCl2 
concentration if and only if the mechanism of regeneration is from 
dissolved O2 alone. In other words people seem to be running 
HCl+CuCl2+O2 at far lower concentration than what they should. So I'm 
wondering who uses HCl+CuCl2+O2 and at what S.G and what are their 
experiences ?

Adam