Homebrew PCBs

Simao Cardoso wrote:
> On Tue, 2009-04-07 at 21:22 +1000, Adam Seychell wrote:
> 
>> Most people who produce ammonium persulfate would do so by
>> electrolysis 
>> at cold temperatures with platinum anode at high current density in a 
>> solution of high concentration of ammonium sulfate. The solubility of 
>> persulfate is significantly lower than sulfate and allows separation. 
>> High anode current densities increase persulfate/oxygen ratio since
>> some 
>> water electrolysis is unavoidable.
>>
>> I don't think any the chemical reactions you describe would make 
>> persulfates.
>>
> 
> Adam, very thanks, you cleared my doubts on this.
> Still, there is 2 other questions that I looking for any comment. 
> 
> Is ammonium persulfate reusable? like sodium persulfate or cupric
> chloride.

Sodium and ammonium persulfates behave very similar, and you cannot 
reuse either of them. Oxygen (from H2O2 or O2) regenerated cupric 
chloride is the only practical reusable etchant for homebrew PCBs.

> 
> Is possible to copper electroplate pcb boards in a sodium persulfate
> bath?? Using copper anodes and when the bath is copper saturated. 
> This last question is strange, but is why i wish to have it this bath,
> if could be possible a 2 in 1.

You can copper electroplate from just about any solution containing 
copper ions, but the question is can you electroplate with thick smooth 
ductile uniform deposits. With all the effort that goes into formulating 
a copper plating solution, I highly suspect you won't find anything 
useful from spent etchants.