Hi Bill,
--- In
Homebrew_PCBs@yahoogroups.com, William Blair <wbblair3@...>
wrote:
> You're using inkjet transparencies in a laser printer, correct?
Did you determine that laser
> transparencies wouldn't work as well? If they don't work as well,
is this because inkjet
> transparancies have some kind of coating or finish that helps in
the transfer of toner to the PCB?
Yes, I'm using inkjet transparencies in a laser printer. I tried
several kinds of laser transparencies and, as you mentioned, it's
the coating on the inkjet transparencies that hold the ink that
makes it release the toner. I also tried transparencies for wax
(Tek Phaser), they were slightly better than laser transparencies;
but nothing had worked better for me than injket transparencies. No
scrubbing, no guessing if toner is melted enough, no blind alignment.
When I used laser transparencies, I found that removing it when the
toner was hot/melted worked best. If I let it cool, the
transparency had a greater affinity for the toner.
With the inkjet transparencies, I let the toner melt and remove the
transparency after things have cooled; but are still warm. There's
some residue from the transparency that I remove with soap, water,
and a tooth brush. You can leave it on, but etch time seems longer
and the residue ends up in the etching solution.
> What brand of transparencies are you using? Do the inkjet
transparencies show any sign of melting
> or shrinking under the iron?
I'm using HP inkjet transparencies. I bought a bulk pack and
there's no part number. I put a paper towel (doubled over) between
the iron and transparency. If the iron touches the transparency, it
will melt, but no problems with shrinkage. A little curling around
the edges from downward pressure, but no distortion over the board.
The paper towel might stick to the transparency. I lift the paper
towel after 10-20 seconds while holding the transparency down so it
doesn't shift. After a few lifts, the transparency gets it's fill
of paper fibers and things stop sticking.
I put the board on a block of wood covered by a doubled paper towel.
> What do you use to remove the toner from only the solder areas?
I use acetone on a cotton swab. You'll need to experiment with how
much to apply. Too little and the toner smears and makes a mess.
Too much and the toner ends up getting embedded in the board. Small
toner smudges can be removed with anhydrous isopropyl alcohol and
some rubbing with a cotton swab.
> I assume you mean laser copies using _paper_ rather than
transparencies?
I tried paper, laser transparencies, and injket transparencies.
Regards,
Dennis