[sdiy] Photosensitive PCB's

[Scott Bernardi]

I use the pre-sensitized positive PCBs, exposed for 10 minutes with a
fluorescent lamp. The lamp is an assembly I bought from Circuit Specialists
http://www.web-tronics.com/ for this purpose; I think it's a special tube that
has more UV than standard tubes.

Michael Schulze wrote:

> I'ma having a hard time getting the photo sensitive pcb process to work.
> I've sprayed my own boards and exposed them with negative art.  When I etch
> there seems to be not enough contrast between light and dark, so the traces
> are not clearly defined.  By the time I can see the fiberglass in between
> the traces the traces are half gone too.
>
> Maybe I am spraying too much coating on???
>
> I've ordered the positive boards to see if that is easier.
>
> Any suggestions on suitable light sources for positive vs. negative boards?
> Seems sunlight is too unpredictable - 4 minutes of noon sun in Ohio is not
> the same as 4 minutes of noon sun in Florida!
>
> > From: René Schmitz <uzs159 at uni-bonn.de>
> > Date: Fri, 24 May 2002 17:15:57 +0200
> > To: "Sandro Traversi" <straversi at libero.it>, "Michael Schulze"
> > <michael.schulze at oberlin.edu>, <synth-diy at dropmix.xs4all.nl>
> > Subject: Re: [sdiy] thermistors
> >
> > At 16:06 24.05.02 +0200, René Schmitz wrote:
> >> low resistance when some threshold voltage is reached. Ususally they
> >
> > Nonsense, instead:
> > *high* resistance when some threshold *temperature* is reached.
> >
> > Cheers,
> > René
> >
> >
> >
> >
> >
> > --
> > uzs159 at uni-bonn.de
> > http://www.uni-bonn.de/~uzs159
> >
> >
> >

--
Scott Bernardi
sbernardi at attbi.com