Homebrew PCBs

Stefan Trethan wrote:
> Oxygen doesn't either, but accelerates any fire.
> 
> I don't think there is a danger.

Though arguably that would make the HCl+H2O2 mix more risky near 
furnaces, etc. (though isn't the combustion section of most modern 
boilers effectively sealed off from the outside air?)

Academic point, really. I'd be more worried about high-concentration 
HCl+H2O2 -- isn't that a so-called "piranha acid" mix, or am I thinking 
of something else?

(But from what I've heard it's also a precursor to CuCl etchant, which 
is -- AIUI -- about as hazardous as FeCl, so it all goes full-circle in 
the end).

If you're using FeCl, I've been told mixing it with Plaster of Paris 
will neutralise it (this was in the datasheet for a bottle of FeCl I 
bought years ago). Though IIRC the more commonly accepted method is to 
mix it with sodium carbonate or sodium bicarbonate until the pH drops a 
little past neutral, then filter out the precipitate. The liquid is salt 
water (NaCl+H2O) and the precipitate is an iron-copper mix of some 
description.

Been a while since I did chemistry though, and I wasn't terrifically 
good at it to begin with...

-- 
Phil.
ygroups@...
http://www.philpem.me.uk/