Homebrew PCBs

Howard Payne <howard_g7lqy@...> writes:
> PS. anyone help with a good etchant ?

I also went with the acid-peroxide etchant, but after a few uses I
realized the peroxide would degrade before I could convert the
solution to a cupric chloride etchant, so I let a half liter
evaporate, added a half liter of peroxide, and dumped in a quarter
pound of copper pipe scraps (a 3.5 liter solution).  A few days later,
I had a jade green CuCl etchant!  It's very shelf-stable, I leave it
sitting on the bench and just warm it up whenever I need it.

If I were to do it again, I'd mix a fresh 3-4 liter batch of
acid+peroxide and dump the copper scrap in immediately.  But only
because I want a "set it and forget it" etchant bath ready.  For
one-shot, might as well use the copper on the PCB to convert it :-)

Note: even with a small one-shot bath, save it!  Next time, ad more
acid+peroxide and etch.  Keep doing that, eventually you will have a
large amount of CuCl etchant, ready to go at any time...

Now, if you're etching a LOT of boards, don't bother with the scrap -
you'll convert it fast enough just with etching.