Homebrew PCBs

In case you don't know it already, check out this page by Adam Seychell:

<http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/index.html>

It does not cover H2O2 regenerated CuCl which can have a faster etch
rate, possibly because some CuCl is immediately regenerated at the
copper surface.

HCl and H2O2 concentration most definitely has an influence, I timed a
very tiny sample at less than 10 seconds to etch a PCB blank. Those
concentrations are not practical for normal use.

I have observed regular etching times from something like 10 minutes
to several hours with my setup. The several hours was when I did not
add any HCl or H2O2 and the etchant wasn't regenerated.

Even with several hours etching time I do not see any bad
under-etching, or pitting. I have mostly double sided stock but prefer
single sided designs, so the back side hogs easily two thirds of the
etching time while the artwork side is already done much sooner. If
I'd see problems with underetching I'd do something about that, but so
far there are none. I use mostly 10mil/0.25mm minimum trace width.


ST