Re: Printed Circuit Board Supplies

Joh, what's your source for the dry film resist? Is it available in
less than industrial sized quantities?

I'm a little torn on this. I don't make a lot of boards. I like the
ammonium persulphate etch, but disposal is a problem and it doesn't
keep like ferric chloride. Now I have a gallon of copper sulphate to
get rid of.

I recently picked up a nice plotter cheap to use as a basis for a cnc
pcb mill. That will be a fun little project and should be a nice first
cnc project. I think this is useful for me given the quantity of
boards I do and the point that you don't have to have any chemicals
around.

Still, you can't beat a photographically produced board. The Green
Circuit folks also had an etchant recipe that you could keep going
forever so there really isn't much of a disposal problem if you go that
route.

Like I said, I'm torn. I'd probably like to be able to do both.

BTW, this was driving me crazy, so I decided to track down the PCB
articles on the multilayer conductive ink boards. It wasn't in Nuts and
Volts after all, it was in Midnight Engineering. Back in '93 they ran
a series of articles called 'The Environmental Circuiteer' written by
Ron Reed of Think & Tinker. The last article in the series even tells
you how to do through-hole plating. Their web site is at
www.thinktink.com and has lots of good stuff including the etchant
recipe, but it doesn't look like they sell the conductive ink described
in the article anymore (they do have stuff for plating holes). I also
can't find any mention anywhere of their alternate source - Minico
M6300. Anyone have a source?

Paul

>
> From: Jon Elson <jmelson@...>
>
>
>
> I use DuPont Riston dry film resist. Having tried a number of other
> resists over the
> years, I can say that nothing else comes close! The resist is almost as
> tough as
> a good solder mask! It takes a serious accident to scratch it, and it
> is impervious
> to hours of soaking in hot etchant. The developer is sodium carbonate,
> a relative
> of baking soda.
>

--
Paul Amaranth | Rochester MI, USA
Aurora Group, Inc. | Systems & Software
paul@... | Unix / Windows / NT