Homebrew PCBs

Hi,

After successfully getting my CNC rig working for PCB drilling runs
(updated info/photos at http://www.freenet.org.nz/cnc), I tried using
the rig to draw etch-resist artwork directly onto the copper surface.

Following recommendations on other websites, I'm using a Staedtler
Lumocolor 313 superfine red pen, which is wonderfully etch-resistant,
dissolves quickly with acetone, writes finer and is more easily
available and 1/3 the price of 'dedicated etch-resist pens' from
electronics shops.

However, the result was not good. Even the 'superfine' variant of this
pen writes a 0.7-0.9mm line, way too thick for my layouts. Also, with
the relatively slow speed of my CNC transport, the pen tends to bleed
out to a thicker line.

I notice from some pcb sites that some people rip the guts from the pen
and insert the ink-bearing felt into a plotter pen. That might be an
option, but such pens might be hard to get given that plotters are no
longer in vogue.

I've thought of mutilating a Staedtler 0.1mm black felt-tip pen, pulling
out the black felt tank, running the pen dry, then inserting the red
lumocolor in its place. But I thought I'd ask here before destroying
$7-$10 worth of pens.

Are there any simple ways to get this pen to deliver a thin (<0.4mm)
line? Or should I stick to the thermal toner transfer which I've already
got working?

-- 
Cheers
David

--- In Homebrew_PCBs@yahoogroups.com, David McNab <david@r...> wrote:
> Hi,
> 
> After successfully getting my CNC rig working for PCB drilling runs
> (updated info/photos at http://www.freenet.org.nz/cnc), I tried using
> the rig to draw etch-resist artwork directly onto the copper surface.
> 
> Following recommendations on other websites, I'm using a Staedtler
> Lumocolor 313 superfine red pen, which is wonderfully etch-resistant,
> dissolves quickly with acetone, writes finer and is more easily
> available and 1/3 the price of 'dedicated etch-resist pens' from
> electronics shops.
> 
> However, the result was not good. Even the 'superfine' variant of this
> pen writes a 0.7-0.9mm line, way too thick for my layouts. Also, with
> the relatively slow speed of my CNC transport, the pen tends to bleed
> out to a thicker line.
> 
> I notice from some pcb sites that some people rip the guts from the pen
> and insert the ink-bearing felt into a plotter pen. That might be an
> option, but such pens might be hard to get given that plotters are no
> longer in vogue.
> 
> I've thought of mutilating a Staedtler 0.1mm black felt-tip pen, pulling
> out the black felt tank, running the pen dry, then inserting the red
> lumocolor in its place. But I thought I'd ask here before destroying
> $7-$10 worth of pens.
> 
> Are there any simple ways to get this pen to deliver a thin (<0.4mm)
> line? Or should I stick to the thermal toner transfer which I've already
> got working?
> 
> -- 
> Cheers
> David


David< I have pulled apart the pens you have listed and squashed the
ink out using a pair of pliers.
I have used a staedtler pen and modified holder to suit a Roland pen
plotter, the pen tip is very small I can't remember the pen number off
the top of my head but I will find it if you need it. The pens are
still available in Australia so should be all right everywhere else.
Philip

On Mon, 11 Jul 2005 22:50:04 +0200, David McNab <david@...>  
wrote:

>
> Are there any simple ways to get this pen to deliver a thin (<0.4mm)
> line? Or should I stick to the thermal toner transfer which I've already
> got working?
>


you got much the same results i got.
I took it a step further and bought expensive carbide-tipped pens with  
cross-ground tip.

Didn't work because (i think) the trailing edge of this metal "tube"  
scrapes away much of the ink and it is no etch resist layer an more.

I never got plotting to copper to work, and it would have been very slow  
anyway.


IMO you are wasting your time, but with what seems a reasonable idea so it  
isn't foolish.

ST

On Tue, 12 Jul 2005 09:04:58 +0200, electrophilip  
<electrophil@...> wrote:

>
> David< I have pulled apart the pens you have listed and squashed the
> ink out using a pair of pliers.
> I have used a staedtler pen and modified holder to suit a Roland pen
> plotter, the pen tip is very small I can't remember the pen number off
> the top of my head but I will find it if you need it. The pens are
> still available in Australia so should be all right everywhere else.
> Philip


Why not just buy the refill ink bottle?
I still have one here which is very usful to refill the pens, for other  
uses, as i havegiven up on plotting.
The bottle has a refill "port" with felt (the pens are refilled through  
the tip. To get liquid ink you need to make a hole or a syringe with  
needle.


ST