Homebrew PCBs

On Sat, 12 Feb 2005 08:31:08 +1100, Adam Seychell  
<a_seychell@...> 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


Of course, more CuCl means more etching, i guess it is the same with any  
etchant.
I do use H2O2, but i don't regenerate each etch, depending on board size  
each second or third time, when the color gets too dark.
When my S.G. was lower i had to use H2O2 more often, but i don't know  
exactly what it is right now (i broke the glass thing with the rubber ball  
where the hydrometer swims in, stupid me, and since then i haven't  
bothered with measuring. The hydrometer is OK but i need to float it in  
some other comtainer now, which is more work...

ST