Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

----- Original Message -----
From: <christiansen_alex@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, December 02, 2009 1:34 PM
Subject: [Homebrew_PCBs] amonium peroxide how long lasting


> 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

I use FeCl3, but used ammonium persulphate many years ago. The solid stuff
lasts indefinitely provided that it is kept dry.

Leon