James,
People have used layout blue used by metal workers. Make sure
you use a tip that creates enough isolation between traces. If you
don't you will have problems if you tin plate the board. (Problem
reported by Mike of this group to me on my group)
I found and old message on the internet from a robotics group
that used the idea a year before me so I have to credit them for being
first. I could not tell by the message if they were using a plotter or
CNC machine to scratch the board.
John
--- In
Homebrew_PCBs@yahoogroups.com, "James Newton"
<jamesmichaelnewton@y...> wrote:
>
> Haveing just taken a shot at John for being condecending to a new
> idea, I should admit that I also think his Scratch and Etch idea is
> totally brilliant.
>
> Has anyone ever just gone and tried this? I have done it with a
> simple plotter, a scribe in place of a pen, and a sheet of glass
> painted black. It works like a dream. My goal was to make a digital
> sun dial, not to etch PCBs, but I can't see why it wouldn't produce
> finer results than any other method.
>
> The only trick is finding a paint that drys quickly to a hard (not
> brittle or tacky) finish so that it is completely and cleanly
> removed by the scribe. Also, the plotter may need to be a nice big
> one like my tough old HP (God rest its soul) because the scribe is
> going to drag more than a pen... probably.