[sdiy] ammonium persulfate safety

[Maarten Halmans]

> All this talk about melting down your lab bench/microwave/etc. in the
> name of PCB construction got me to thinking about something someone
> once told me.  That is, ammonium persulfate is not stuff you want to
> keep bottled up in storage--it releases lots of O2 or something.  Does
> this sound plausible?  Has anyone had any leaking/bursting bottles?

Nope, I have a couple of bottles standing around for about half a year, no
problem so far. I opened one of them and there was no pressure on it. Just
after putting it in the bottle there is some light gas forming. I keep the
bottles open for about a day or 2 and then close them.

> So, my question is, is this stuff shelf stable?  Like FeCl3, for weeks
> or months at a time?
I only did this with used etchant, maybe it's a different story with fresh
etchant. When I kept the etchant in my tank for a long period of time(2
months) it formed a sort of flakes and became unusable..
I recently switched back to FeCl3 which is much cheaper and it seems to etch
much faster(@35C).
Maarten