Chris,
I use Ordyl Alpha 900, but there are other products around. They are
used to produce PCBs. You may want to contact a board house near you to
ask for a local supplyer and what they use. The "problem" with the
resist is that you usually must buy two complete rolls. The smallest
ones tend to be 150m. But if you are a member of a forum or something
that does the stuff you do (and I get the impression that's the case),
then you may easily can motivate others to buy a set of rolls for a few
members. I did a similar thing. I bought two rolls, used one for my own
needs but sold the other to a group of people thereby cutting my costs
in half. A roll, when stored in a fridge and when you hand cut peaces of
it will last ~2 years. Depending on the product, the storeage capability
depends on the environement temperature (should be below 10 degrees
celsius) and in some cases the exposure to oxygene. The good thing about
the ordyl alpha is that it is not that much critical with regard to
oxygene that said it's sufficient to store the roll in the fridge. :-)
HTH
Markus
Chris schrieb:
>
> 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
> <mailto:Homebrew_PCBs%40yahoogroups.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
> >
>
>