Homebrew PCBs

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 2¢
> 
> Markus
>