Dennis,
Many thanks for your extremely informative posts! I'll be trying your
method and will post my results along with info on some other PCB
manufacturing experiments I've been doing.
Thanks!
Bill
--- In Homebrew_PCBs@yahoogroups.com, "dl5012" <dl5012@...> wrote:
>
> 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
>