Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Chris,

I don't think that you can much optimize your process by changeing the
etchant. You easily can optimize the etching process itself though. You
may want to optimize some other steps in your process too:

a) exposure. Use an exposure unit (self built if you want, there are
plenty of projects/plans around) That way you expose the stuff in as few
as 10 seconds. The key factor here is the light source which should be
ultra violet.

b) The resist you use seems quite odd to me (requiereing wet
application). There is dry film resist out there which should do much
better. Simply laminate that one onto the brass. Should be a matter of
~3 minutes and not fuzzing around with water etc.

c) Build a bubble etcher with a heater element in int. That way I'm sure
you bring down your etching times significantly.

You CAN use alternative etchants (and others here surely will give you
replies), but be warned that the alternatives are much more agressive to
the envireonement or cost significantly more because you can only use
the mixture for one (or very few) etch process(es). The nice thing about
Fe3Cl is that it lasts very very long when compared to the alternatives
and it's dirt cheap, and is also less dangerous. Other etchants are
extremly agressive to all your metal stuff surrouding the area where you
etch. I mean it, you would not be the first one using this stuff just to
find out that all of a sudden a lot of things around you get an instant
rust layer.... Natriumpersulfat on the other hand is compareably
expensive and does not last very long.

Just my 2¢

Markus