I thought about doing this several years ago and called the manufacturer of
my plotter (Graphtec) and they put me in contact with someone who was doing
that with black India drafting ink. I never tried it. Has anybody elde
tried that? It's cheap and readily available at any drawing supply or
office supply store and can be put in any refillable plotter pen.


At 01:56 PM 9/12/97 -0400, you wrote:
>I have a HP 7221 (7225?) that I have used many times to plot an etch
>resist pattern on copper clad board. I took a standard HP plotter pen,
>removed everything except the body, then bored it out in a lathe to fit
>a permanent ink pen. (You can probably do this by hand reaming with an
>appropriate set of drills or careful sanding and filing.) I found that a
>Sanford ultra fine point Sharpie worked the best. You need to adjust you
>pen speed and width settings to get the best line while still moving
>fast enough so that the pen tip does not dry out. Width setting is
>important so that you don't overlap what has already been plotted as the
>partially dried ink will clog up the pen tip. Likewise, don't let the
>pen dry out in the holder between plots. I used drafting tape to hold
>the board in place. I successfully did a design once with pads for a
>flat pack IC that came out useable.
>
>I also experimented with other brands of pens (and pencils!). I never
>was able to get good results with a Berol Fine Point Permanent (which
>is, BTW, the "etch resist" pen that GC electronics, Kepro, and Radio
>Shack used to sell for more than a whole box of the same pen at a office
>supply store). I never could keep the tips from drying out during the
>plot. I have also found that for extremely fine line drawings on paper
>or vellum (not film), a Pilot Precise roller ball gave excellent
>results. Text smaller than 1/16 inch was clearly readable!
>
>
>Frank Richterkessing
>
>FRANK.RICHTERKESSING@APPL.GE.COM
>