Homebrew PCBs

Hi Listies,

My first "exposure" to making circuit boards was in an early class in
college (late 60's).  The instructor had us put masking tape on the
board material, draw the circuit, then take an Exacto knife, cut out
pads and traces.  Finger nail polish was then dabbed into the removed
trace and pad areas, and let to dry.  When dry, the tape was pealed off,
leaving a resist pattern that could then be etched.  Mind you, these
were for audio boards.

Since then I've done a lot of wire-wrap.  But that takes a lot of time. 
Advantage is that you can remove and move wires.  I use a "Manhattan"
layout, with each wire making only 90 deg turns to get to it's
destination on the board.  Every wire stays at it's proper level, and no
rat's nest is allowed.  I can "tug" on a wire, and see where it is
going.  I thought about a CNC controlled table, that would position my
professional WW gun to the pin wanted.  It would then "move" to the dest
pin (all controlled by a CNC file generated from the schematic capture
program's net list).  There are PCB board systems that rely on a
"stitch" system, where wires are "welded" onto pads.  That's something
that could possibly be built by hobbyists (the XY positioning system),
if we could figure out how to weld the wires.

Too bad we can't use a swivel Exacto blade, and cut the same, this time
leaving the traces and pads intact.  Then etch.

I also like the "scribe on layout dye and etch the isolations" that has
been proposed and tried to a limited extent.  

Just using a resist pen to draw the pads and traces still appeals to me,
and who knows, what about a "resist spray" that is applied through
apertures, much like Gerber.  Or how about John's idea of directly
exposing photo-resist with a high intensity light, again using an
aperture system?

But I gotta LOVE mechanically etching (milling) my boards!  Fits in with
CNC mills!

Alan  KM6VV


crankorgan wrote:
> 
> Hey Gang,
>          Many years ago I made some double sided boards for a guy
> at work  building a power amp. I took the PC layout from the magazine
> he had. I taped it to a board. I used a sharp point to mark each
> component hole. I then drilled the hole locations. I cleaned the
> board with steel wool and dried it. I wore white cotton gloves during
> the next step. I took a marking pen. I put a dot of ink at each hole
> on both sides of the board. I then turned the dots into pads. Then
> it was connect the dot time. I then etched the board. Success!
> 
>                                                 John