wrote in message oups.com...
RST Engineering wrote:



But the paper
HAS to come apart if we want to leave ONLY the thermo-plastic material
bonded to our circuit board. So use the cheap stuff. And soak it in
warm soapy water. Then scrub it with a tooth brush or whatever -- get
ALL of the paper off of the thermo-plastic.

One of those green kitchen pot scrubbers does a pretty fair job getting the
paper off while leaving the toner on the board.

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Agree.

Initially, I went at the paper in a very tentative way, worried that
any amount of scrubbing would remove the toner. Which is something of
a joke. If you've used enough heat, the toner STAYS, despite scrubbing
with everything that came to hand.

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Not only does this method allow you to make near-perfect reproductions
of data plates and the like, it allows you to etch logos, names and so
forth onto aluminum tool boxes, prepare 'engraved' plates for
presentations, and so on. The tricky bit here is that you are
typically etching in the positive sense rather than the negative. I
found the best way to do this was to make individual masks -- OIL
PRESSURE -- 10 A -- TACHOMETER ...or whatever. The characters
themselves are left clear and the mask is cut to leave a border of
toner. These masks are then ironed on to the panel, plate or whatever
in the usual manner. (Large pieces, such as a tool box or instrument
panel, will benefit from being pre-heated.) Once the masks have been
transferred to the work-piece all of the open areas are sealed with
something that will resist the etchant; regular enamel paint works
okay.

This is a case where acid has a definite advantage, since the object is
to remove a signficant amount of metal.

Once the piece is finished, the etched areas may be filled with a
contrasting paint.

The joke here is that I spent a couple of years making instrument
faces, 'antique' compases and the like before I realized the method
could also be used to make circuit boards :-)

-R.S.Hoover



Would a color copy (negative) transfer the same way? This way you could make labels and placards and then iron them on,
color and all...