Homebrew PCBs

Once it is mixed in water, the clock is running. I have found that if I mixed
more than I needed and etched a small board, I could come back in a week or so
and still etch some more as long as I heated it. I think if you let the unspent
liquid cool off and bottled it, it may keep a little longer.
Rick

Leon Heller wrote:

> ----- Original Message -----
> From: "Phil" <phil1960us@...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Thursday, February 26, 2004 3:47 PM
> Subject: [Homebrew_PCBs] shelf life of ammonium persulphate
>
> > I've read the archives and googled.  I saw several references to
> > shelf life as a negative of AP.  Does anyone know what the shelf life
> > is? I am assuming that the powder/crystals is indefinite but the
> > solution is not.  I know AP is not the prefered etchant around here
> > but have some and will probably use it.
>
> I used it a long time ago and it didn't keep for more than a couple of days.
> I used to mix it fresh each time I did any etching; the boards were quite
> small.
>
> Leon
> --
> Leon Heller, G1HSM
> Email: aqzf13@...
> My low-cost Philips LPC210x ARM development system:
> http://www.geocities.com/leon_heller/lpc2104.html
>
>