Homebrew PCBs

On Thu, 08 Jul 2004 16:34:46 +0200
Stefan Trethan wrote:
> Most time consuming right now is the polishing process to get the
> paper residue
> off the toner. Still looking for a better way (but found no paper that
> 
> leaves
> no residue and works well).

Stefan, I found a trick for the component print:
Since the paper residue is barely visible when it is wet, I tried to
spray the component side with "Kontakt Chemie Plastik 70" spray from CRC
Industries.

It works great, I don't have to remove all the paper residue. Since the
spray is 'wet', it kind of suspends the paper residue in that state
under the plasic spray after its dryed.

For solder side component print, the plastic stuff wouldn't work, of
course. Maybe "SK10 Loetlack" spray from the same company works?

But be careful not to move the board until the plastic layer is dry
because that stuff also acts as a good solvent for the toner.

On my first try, I was shaking the board so that the plasic would
distribute evenly which led to the component print to 'swim' around.

This also has a positive effect: I now use that same spray to remove the
toner from the solder side after etching. It works better than the other
things I tried. Just don't let it dry.

Here are some pictures of my boards:
http://cockpit.varxec.de/electronics/gal/phcc1_galleryidx.html
http://cockpit.varxec.de/electronics/gal/DOA1_galleryidx.html
http://cockpit.varxec.de/electronics/pickeymatrixpcb_galleryidx.html

Finest structures: 12mil trace/12mil space
Printer: HP LJ IIP/IIIP (basemodel was a IIP, but got some 'implants'
from a IIIP)
Toner: EPL (i think)
Paper: Reichelt Elektronik Catalog paper
Transferred with a standard clothes iron, second highest temp./moderate
pressure


This picture shows the board where some pieces of toner 'swam' away:
http://cockpit.varxec.de/electronics/gal/phcc1_gallery27.html


Regards,
Manuel