"lcdpublishing" <
lcdpublishing@...> writes:
> First, I was amazed at the speed of etching - very fast - even faster
> if you agitate the circuit board. I didn't use a bubbler as am not
> sure if I am suppose to.
Don't need to yet. The initial bath is very agressive, mostly because
of all that H2O2 in there.
> 1) How will I know this is now Cupric Chloride?
It will be a dark emerald green when converted. You won't even be
able to see the board in the tank.
If you haven't already, read all of this:
http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/The photo on that page is what my etchant looks like at the moment.
> 2) Should I use a bubbler with Cupric Chloride?
Yes, partly to help with etching and partly to regenerate the
solution. Otherwise, you have to keep adding H2O2 and it dilutes the
solution. Regenerating with the O2 in air helps keep the solution
under control.
> 3) Does Sharpie pen ink hold up as a resist?
Probably, but that's just a guess.
> 4) With this, is there any gasses given off that I need to be aware
> of?
Chlorine, especially if you use a heater. Provide good ventilation.
Don't set up near anything metal. Keep your etchant tank sealed when
not in use.
> Any other advice or suggestions would certainly be appreciated.
The solution has a short "shelf life" in it's initial state - the H2O2
breaks down and plain HCl won't etch copper on its own. It's best to
either etch a lot now and convert it quickly, or dump some waste
copper in (old pipe fittings, for example) to convert it separately.
I calculated about half a pound of copper per 3 liters of solution
gets you to the low end of CuCl etchant - leaving room for another
half pound of copper from etched boards before you have to start
worrying about what to do with it.
Alterately, leave room in your tank and keep some H2O2 around to dump
in before etching.