Homebrew PCBs

I am not sure if you mean Ammonium Peroxide or Ammonium Persulfate but I had some quantity of the latter sitting around for 15 years and it all went bad and would not etch anything when I tried to etch a board.  Not sure what it decomposed to but I suspect it reverted to Ammonium Sulphate.

Craig

--- In Homebrew_PCBs@yahoogroups.com, christiansen_alex@... wrote:
>
> hell members
> I often see,that there are qualified chemist people here in the group.
>  
> So I have a question about the peroxide types etchants.
> Its often told that they only last  4 weeks,if they have been dissolved in water..
> How does it look when the peroxide is in the solid form ? does it have a limited liftime ?
> 
> So does it take much of liftime ,if it is stored and it is not dry.
> and how long does a solution with water actually last ,to be usefull.
> thank you for any response 
> alex
> denmark
>