Homebrew PCBs

Jim Miller wrote:
> I just read Adam Seychell's page on various etching solutions.
> 
> It seems to me that the only disadvantage to ammonium persulfate is slow
> etch speed at room temp.

It needs heating  30 to 70C to get practical etch rates. Its not as 
economical as FeCl3 and other chloride based etchants. I guess some 
people use it because they like to see the PCB being etched.