Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, Robert Hedan <robert.hedan@...>
wrote:
>
> > -----Message d'origine-----
> > De : Homebrew_PCBs@yahoogroups.com 
> > [mailto:Homebrew_PCBs@yahoogroups.com] De la part de dagmargoodboat
> > Envoyé : juin 28 2006 21:13
> > À : Homebrew_PCBs@yahoogroups.com
> > Objet : [Homebrew_PCBs] Re: Toner melting points, pt. 2
> > 
> ...
> > Using Staples' Picture Paper, my first try through
> > the laminator gave a perfect--and I do mean perfect--
> > transfer of a junk board with some 0.006" lines onto
> > 0.020" double-sided circuit board.  Very nice.
> > 
> > The second attempt--on a real board to be etched--
> > was not perfect though.  Traces had a few gaps, and
> > some pitted / ragged edges.  Mostly okay, but not
> > acceptable.  I'm using 0402 parts, and need fine
> > lines. Subsequent trials have not improved.
> ...
> > 
> >   Best,
> >   James
> 
> 
> Welcome James,
> 
> Since you were able to get perfect results on the scrap board, I would
> suggest looking more into the preparation of the PCB surface.  The scrap
> board might have had better 'stiction' than the newer board.
> 
> My prep:
> 
> - XXXX fine steel wool, scrubbed in both directions, X and Y.
> - clean with acetone.
> - clean with 99.9% isopropyl alcohol.
> - wipe alcohol residue dry.
> 
> This cleaning process is extremely exaggerated, but I never have to
start a
> board over 'cause toner doesn't stick (I'm using Pulsar Paper and a
GBC H300
> laminator).
> 
> Robert
> :)

Thanks Robert,

I thought that too, and decided to test the idea.  Wanting
to eliminate board prep, as well as transfer pressure,
thermal mass, temperature, and a bunch of other variables
from the equation, I cut another identical image--printed
on the same panel--then tried adhering the decorative
transfer foil I'd mentioned before.

Namely, I wanted to first answer the question "Will the
toner adhere to anything?"  Foil adhesion is quite easy
compared to transferring toner to a PCB.

I found the toner does *not* always fully accept the
decorative foil.  The foil shows the same defects as the
failed-transfer boards. To rule out defects in the foil,
I tried shifting it around, exposing new areas to the
bare toner areas.  Still no transfer.

I'm considering whether there might be some sort of toner
surface contamination.  The failed panels, however, came
from the same sheet as the perfect panel. Still thinking
about this...

My board prep *was* slightly lax--stainless steel
potscrubber, with soap, then Comet cleanser, towel
dry--but it's robust enough to cut through the dull
oxide and leave a mirror finish on the Cu.  Same
procedure as used on the "perfect" trial board.

I'll post any fixes I devise.

  Thanks again Robert,
  James