Re: gEDA-user: New user to PCB - what does this error mean?

[DJ Delorie <dj@xxxxxxxxxxx>]

> I like to keep etchant around -- I use CuCl2 + 2HCl --> H2CuCl4

This is what I use.  Once converted to CuCl2, it's shelf stable and
there's no waste.

> The HCl to use is 35% (swimming pool stores),

Also, hardware stores sell it in the paint isle - it's a primer for
painting cement.  Might be labelled "muriatic acid".

> the H2O2 is 35 % (hydroponics supply store).

Most of us use the 3% you can buy in a drug store.  1 part 37% HCl to
2 parts 3% H2O2.  If you use 35% H2O2 you can dilute it.

> It's slower, but possible to just use air and a fish tank bubbler to
> activate the solution instead of H2O2.

What I do is air regenerate.  Less waste, as the solution doesn't grow
as fast.  The regenerated solution is shelf stable, too, unlike H2O2
solution, and the air bubbler is needed to agitate the solution during
etch anyway.

> Add HCl to get emerald green -- yellow green is too much -- on the
> edge of releasing chlorine gas.

Or use titration to measure pH.  For all the nasty chemistry, see
http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/

(mine looks just like the photo on his home page)

> Add H2O2 to lighten spent solution.

H2O2 turns spent (brown) solution to fresh (green) solution.


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