Markus,
Thanks, I will just stick to Ferric Chloride.
If it's daytime I expose outside in about 1 minute.
I am interested in the resist film you mentioned. The stuff I use if
from Micro Mark and I think is what people use to sandblast images on
glass. Can you post a link to where I can buy what your talking about?
Thanks
Chris
--- In
Homebrew_PCBs@yahoogroups.com, Markus Zingg <homebrew-pcb@...>
wrote:
>
> 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 2ยข
>
> Markus
>