Homebrew PCBs

Lukas,

<10 mil traces/spaces are touch-and-go. If you use a fine enough mesh 
(remember the silk screen layer on your board is created this same way) and 
print carefully (you get the feel after a while) you can get 10 mils. I 
gained alot of confidance doing this after silkscreening T-shirts as a 
hobby.

There may be a screen product available but coating your own is a piece of 
cake. 1.) buy the fabric from an art shop, etc. 2.) buy the 2-part emulsion 
(non-toxic, easy to mix & not too expensive) also from an art shop. 3.) coat 
the screen with a brush or squeegee and let air dry (in the dark) 4.)lay 
your artwork on top (cover with a piece of glass to hold it down) and expose 
to sunlamp or UV for 10 minutes. 5.) wash the screen and non-exposed 
portions rinse away. 6.) you now have a reusable screen good for many, many 
prints.

Bob

>Bob, so can you get down to 10 mil traces and spacing? I have thought about
>silk-screening resist in the past, but have never had the guts to try it :)
>
>A while back I ran into a craft type website that had a screen product that
>one could run through a laserprinter directly instead of using a photimage
>method to get the image onto the screen, but can't find the link in my
>favorites right now.
>I'll keep on looking.
>
>Lukas Louw
>
>
>
>
>
> >
> > I have had great success with this process and making printed circuit
> > "silkscreens" (also very easy) but instead of transparency paper (too
> > expensive) I used a very light weight "onion skin" type writing paper
>(about
> > $2.00 for 50 sheets) that took the ink very well but still let the UV 
>from
>a
> > sunlamp through. I placed this over very fine printing silk set in a 
>frame
> > that I had coated with silk screen emulsion (artshop) for about 9 
>minutes.
> > After the screen was made I printed the image to circuit boards using a
> > squeegee and black acrylic ink. Let it dry and etched it. washed the
>acrylic
> > ink over with a scrubbee. I made a ton of boards and those that printed
> > badly, I just washed the acrylic ink off and printed again. Good for all
>but
> > very fine traces (like 5 mil). This method is cheaper than transfer 
>paper
>or
> > anything else (IMHO)
> >
> > Bob
>
>
>
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