Homebrew PCBs

"Chuck Hackett" <egroupscdh@...> writes:
> I thought that 3% H2O2 contained too much water to be an effective
> etchant - or am I confusing that with H2O2 needed to "replenish" a
> used etchant solution?

Yes, stronger H2O2 is best for replenishing, although you *can* do it
with weaker stuff if you evaporate off enough water first.  For
starting a new solution, though, the 3% is just right.

> If so, I assume you just start with fresh Muratic acid and 3% H2O2
> rather than replenishing it?

Some people do that, if you don't mind neutralizing the solution and
disposing of it.  If you neutralize it with NaOH you get mostly salt
water, with a little copper in it.

What I did was convert it to a CuCl etchant, which can be regenerated
with an air bubbler, so there's no need to neutralize it or dispose of
it.  http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/