Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> wrote:
> The clearest etchant I am aware of is ammonium persulphate (AP).  As
> it gets consumed, it turns a rather pretty shade of blue but is still
> clear enough to see through.

Is this (AP) something that you can make from common products or is it 
something you purchase for this purpose?

Thanks

Chris