🚀 go-pugleaf

In article <1992Dec21.152708.11873@kong.gsfc.nasa.gov> stephens@kong.gsfc.nasa.gov (mark stephens) writes:
> Are these useful?

Yes.  But not as useful as wire-wrap or Slit-N-Wrap.

> They are the "pencils" which wrap a wire around a post
> and you then solder it. [...]  Etching seems to be a tad
> much for (probably) one shot boards and wire wrapping might be overkill. 

For one-shot boards (largely for ICs), I've used:
- hand etched PC boards using India ink (hand-drawn on!) for resist
- hand etched PC boards using photo resist
- hand etched PC boards using silk-screened ink resist (from photo)
- Vector wiring pencil (P178-1)
- Vector Slit-N-Wrap pencil (P180)
- wire-wrap (tm Gardner Denver :-)

For reliability, I prefer wire-wrap 1st, then Slit-N-Wrap.  The wiring
pencil is well down the list.

I found that the wiring pencil was useful for a very compact board, but
you have to be very careful not to melt (a) the socket (b) too much
insulation along the wire.  The docs say "use a 750 degree tip" and
they mean it.  I used an 800 degree tip on my Weller temperature
controlled iron.  This is a bit silly: buy a $5 tool and you need to
use a $100 soldering iron with it.  It can be made to work though,
I built a complete CMOS microcomputer with it.

> With the pencil, do you need special posts for inserting into a perf
> board?

I always used solder-tail sockets that I epoxy'd down.  Alternatively,
I would scotch-tape the sockets in place, turn the board over and
solder all the Vcc and GND pins and remove the tape.  You can wire
directly to cut-off and bent component pins (resistors, etc).

But I'd forget all that.

I'd recommend a simple and cheap hand-wire-wrap tool if you just
have a small board (up to 25 ICs) to do.  These look like this:

             ____________
============|_____O______|=========

^                 ^                ^
|                 |                |
wrapping end    stripper     unwrapping end

(sorry about the ASCII pix)

... and take 30 gauge wire, and cost about $7 or so.  All the tools you
need are:  the above, a small side cutter (4"), needle-nose pliers (5")
and it's helpful to have a very small crochet hook to snag wires and
shove them around.  The cutters and pliers should be spring-opening if
you can get 'em.

Have fun!

--
"Eventually, I decided that thinking was not getting me very far and it
 was time to try building."           -- Rob Pike, The Text Editor sam
      bmw@isgtec.com   [ ...!uunet.ca!isgtec!bmw ]  Bruce Walker