Homebrew PCBs

On Tue, 2009-04-28 at 20:55 +0100, Len Warner wrote:

> >[snip most of Simao's reply] but to
> >end with all the doubts the etchant reaction is:
> >Na2(SO4)2 + Cu+ --> Na2SO4 + CuSO4
> >Or like this?
> >Na2(SO4)2 + H20--> Na2SO4 + H2SO4 + H2O2
> >H2O2 + H2SO4 + Cu --> CuSO4 + 2H2O
> >basically both are right but the second ends with
> >the speculation that fooled me right?
> 
> Please explain: what speculation? 
The best words your find in this really good written post.
http://www.electro-tech-online.com/electronic-projects-design-ideas-reviews/8272-pcb-etchant.html#post668389
He calls it 'Eternally-replenishable Novel Etching Solution (based on
persulfate-type etchant)'. And a something that work like that is what i
was looking but isn't that simple.

> Also note that the
> second of the three reactions is not balanced :-(
I didn't care about it at the moment, none was balanced. The point was
to say that peroxide is formed and is the key in the reaction (i now
think). And not the sulfate ion alone.
> 

>