Homebrew PCBs

thanks...

in fact in the past i did a lot of rework with different "sharpie" like 
pens.
(when i used photoresist and had problems with getting the films/exposure 
right).

most inks in these pens works also with hcl h2o2 if used in the pen they 
are sold for.
these nylon tipped pens sometimes are made like the outline of a star.
the ink is carried through capillary effect and gravity.
(the star shape offers a lot of thin channels, thus a lot capillary effect 
is created)
altso the overall tip is rounded off, as i have seen.
if you drag it along the surface the trailing edge is lifted off the 
surface.
this allows a lot of ink to stick to the surface.

the plotter pens are in principle only a round tube.
in the center is a thin wire which is spring loaded.
(i assume this wire is for aiding in capillary effect and making contact to 
the surface).
the spring loading down the center wire (rounded tip on this wire) is very 
light pressure, thus
it is depressed fully into the tip cylinder when contacting the paper (pcb) 
.
when dragging the metal tip plotter pen the trailing edge is flat against 
the surface.
the ink is only within the tube so the resulting layer of ink is very thin.
there are x grooved tips. this means 4 grooves are cut in the pipe tip to 
make a better
flow of ink. with my carbide pens only the 0.18mm diameter is x grooved and 
i can't see
any difference in ink layer thickness.

i guess this is most of what i know about this stuff.
i wanted to use metal tip pens because they produce a constant line with, 
regardless of pen speed.
maybe i take some photos of the result i get with nylon tip pen (the 
teardrops).


so the main problems i would say are:
a) the copper doesn't "suck up" the ink like paper (it is more like a ohp 
transparency).
b) the expensive carbon tip pens are constructed so that the layer is to 
thin.
c) the nylon tips result in teardrops because linewith is a function of pen 
speed.

st


On Sat, 27 Sep 2003 15:37:29 -0000, Ben H. Lanmon <bhleavi@...> 
wrote:

> GC Electronics is under GC/Waldom   website does not tell you much as I 
> believe that you have to be registered dealer to get to most information 
> on the site.  They do give you access to there Dist. locator but think 
> they are only U.S. and Canada that I saw.
>
> Mouser  www.mouser.com I believe carries the GC Electronics resist pens 
> but don't list them as GC Electronics.  They list two pen widths
> 1/32" and 1/64"   or .79 mm and .39 mm.  these list for $2.48 and $2.64 
> each    Page 1040 in Cat.#615
>
> MG Chemicals has a resist pen  www.mgchemicals.com  I buy MG Chemicals 
> thru Circuit Specialists  www.web-tronics.com  MG Chemicals pen is only 
> listed for use with Ferric Chloride and Sodium Persulfate,  not for use 
> with Ammonium Persulfate.
>
> These pens look just like a Shapie, in fact I use a fine point Shapie to 
> do touch up when needed on my boards, I use Ferric Chloride Etchant.
>
> Ben
>
>
>
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