Homebrew PCBs

the container I have says 250 g/Liter H20 so you should have used 
500g.  I'd expect you to have a strong etching action with that temp 
and concentration.

Phil

--- In Homebrew_PCBs@yahoogroups.com, "Dean Thompson" <deanthom@d...> 
wrote:
> mumin55555 wrote:
> > i tried for the first time to use ammonium persulphate instead of
> > ferric chloride. i built a nice etcing tank with a heater at about
> > 50 degree celcius and an air pump. i used about 1kg of ammonium
> > persulphate with 2 litre of water (at the first place i used much
> > less ammonium persulphate, but when i saw nothing is happening i 
put
> > more).
> > help!!!!!!!!!!!!! i need it very urgent!
> > thanks a lot,
> > mumin.
> 
> I get good results with ammonium persulphate, I use 1 part crystals 
to 5
> parts hot water (75 deg C) as per the directions on the bottle I 
have. Your
> agitation and heating should help speed the etching. Don't make it 
too
> strong. Give it some time, don't just start throwing in more 
crystals.
> 
> Hope that helps
> Dean