Phil,
It just hit me! Besides the paper towels I was also told to build
a rocking table instead of using bubbles. Less mess. I bought a AC
geared motor from Edmund Scientific. A simple cam on the motor shaft
lifted one end of the table creating a wave. The people who were
trying to help me had worked in a PC house that did goverment work. My
problem was I did no shake the little spray can of sensitizer. By
buying a board that was already coated I was able to figure out where
I was messing up. My negative was that red mask on clear. You cut the
red away and leave clear traces. I then bought the pads and trace
tape. They would be laid out on a clear sheet of plastic. I exposed
the board to my shop florescent light for 3 minutes. I think I was
suppose to use UV. A few months later people started using copiers.
They also sold rub on traces back in those days. You had to wear
white gloves and use a wooden burnishing tool. The paper seemed waxy
and it had traces and pads on it. The same method as rub on lettering.
Some of the stuff was made by Calectro or some name like that. Radio
Shacks circuit board kit has alway been crap! I had to drive up the
highway for the good stuff. I used to by blue Vector perfboard weekly.
John
--- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> wrote:
> I've been using paper towels all along and have never had a problem.
>
> --- In Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...> wrote:
> > I called Bounty out of curiosity. I read before about the
> possibility
> > of paper contaminating my boards. Bounty checked with their
> chemical
> > engineers and no, there is nothing that could possibly transfer and
> > contaminate except for the paper that is printed!!!! The paint can
> be
> > dissolved and leave particles or even images as mentioned on the
> > packaging. Hopefully it helps. Mike
> >
> >
> > --- In Homebrew_PCBs@yahoogroups.com, "crankorgan" <john@k...>
> wrote:
> > > Thanks Leon! Now that makes sense. The mistake I was making was
> > not
> > > shaking the spray can of sensitizer. I can't tell you how many
> > boards
> > > I sprayed in the dark. I was allowed to use a small a red light.
> > After
> > > cleaning the board I would stand them up in the dark and spray
> > them. I
> > > then dried them using an old hair drier. The negative was that
> red
> > cut
> > > and peal stuff. I did some boards for a local college through a
> guy
> > at
> > > work. He got his degree and left our company without paying me!
> > >
> > >
> > >
> > > --- In Homebrew_PCBs@yahoogroups.com, "Leon Heller"
> > <leon_heller@h...>
> > > wrote:
> > > > ----- Original Message -----
> > > > From: "crankorgan" <john@k...>
> > > > To: <Homebrew_PCBs@yahoogroups.com>
> > > > Sent: Friday, September 10, 2004 1:15 PM
> > > > Subject: [Homebrew_PCBs] Don't use paper towels
> > > >
> > > >
> > > > >
> > > > > After you clean up your copper surfaces don't use a paper
> > towel on
> > > > > the copper. Air dry the copper. I was told if you rub the
> board
> > with a
> > > > > paper towel it leaves a coating. I think he said it was some
> > kind of
> > > > > silica? Maybe somebody he knows?
> > > >
> > > > Silicone oil, perhaps. It used to be used on the fuser roller in
> > > some Xerox
> > > > copiers. Don't get it in your eyes, it makes them sore for
> several
> > > hours
> > > > (speaking from experience).
> > > >
> > > > Leon
> > > > --
> > > > Leon Heller, G1HSM
> > > > http://www.geocities.com/leon_heller