Do some archive searches in sci.electronics.design or net searches on laser
printer toner transfer for printed circuit boards. Basically, you can print
your pattern on transparency material with a laser printer then transfer it
to clean smooth copper with a clothes iron. Carefully peel off the plastic
and the toner stays on the copper as a resist. Yes, there are some fine
points I'm leaving out because I'm not expert at this. You will have to do
the etching by trial and error, since the rate is temperature and
concentration dependent, but something like 20 to 60 minutes would be my
guess to etch 1/16". You can also buy spray-on photosensitizer to spray on
the copper, then use the transparency as a mask and expose it with UV light
(we use a 500W halogen light at about 2' for 5-15 minutes), then develop and
etch, but this is tricky to get a good coating of the sensitizer so we
usually buy precoated circuit board material.

--
Regards,
Carl Ijames

On 11 Jul 2003 13:24:02 -0700, the renowned
(six-toes) wrote:

i want to etch some printing plates ,first starting with a design in
Coral say and then outputting to a printer to make a etch mask.
i am not sure what method to use to make the mask and how to apply to
the copper using a printer ..
any ideas ?
how long to imerse in the ferric chloride or similar solution?
say to etch of 1/16" of metal.

I've never tried this on thick copper, but as someone else mentioned,
this is one possibility:

1) I assume you just need to etch away a thou or two of copper
(1-oz copper PCBs have 0.0014" thick copper on them)

2) You can buy coated paper that does toner transfer. It's a bit
of a dubious process in my experience, but it does work for
coarse resolution. You print using a LASER printer or
photocopy an inkjet printout onto the paper, then IRON the
paper onto the very well cleaned, slightly roughened and dried
copper. The toner (facing the copper) should melt (might have
problems with such a thick piece of copper, maybe you have
to preheat the copper first), and being a polymer should
stick to the copper.

3) You then soak the whole thing in water until the backing
paper comes off.

4) Then etch in hot FeCl or other etchant, for maybe 10-15min,
preferably with bubble aeration or agitation.

5) Clean off the toner with solvent like laquer thinner.

You'd want to find some way to cover the back of the copper to
avoid wasting most of your etchant (masking tape?), or maybe just
suspend it on the surface of the etchant.

The paper costs $2.50 US a sheet, and you can get it from Digikey and
others.

Some have had luck using ordinary heavyweight (clay) coated stock as
might be used for posters, but I've not tried it.

----

If that doesn't work, and it may well NOT, (one of) the RIGHT way(s)
to do it would be to LAMINATE dry-film photoresist onto the copper,
expose with UV light, develop and etch. Think and Tinker has the film
in relatively reasonable lot sizes last I looked (50' for around $70
as opposed to around $300 for a full roll).

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

In article ,
(six-toes) wrote:

i want to etch some printing plates ,first starting with a design in
Coral say and then outputting to a printer to make a etch mask.
i am not sure what method to use to make the mask and how to apply to
the copper using a printer ..
any ideas ?
how long to imerse in the ferric chloride or similar solution?
say to etch of 1/16" of metal.

thanks

If you etch in ferric chloride, turn the plate upside down so the bite
falls out, otherwise the lines can get rough. You can also use nitric acid
(somewhat more dangerous) and Dutch Mordant (hydrochloric acid with
potassium chlorate). The dutch mordant is the best, but also the most
dangerous, you need a ventilation hood for that.

As for the etching time, it's trial and error. It will vary according to
how much metal exposure you have and how old your acid is (how much it's
been used already).

As someone else noted, put a resist on the back of the plate; transparent
stick-on vinyl works well.

Lots of good printmaking supplies he http://www.graphicchemical.com/

--
Jedd Haas - Artist
http://www.gallerytungsten.com
http://www.antijazz.com
http://www.epsno.com

If the design is simple you can apply contact shelving paper to the
copper and the corel output on top of that. Then use an hobby knife
to cut the design and peel the parts you want to etch. You can also
sand blast instead of etching with chemicals. With sand blasting you
can not go very deep before going thru the shelf contact paper. Works
with glass too.

Dan


In article ,
(six-toes) wrote:

i want to etch some printing plates ,first starting with a design in
Coral say and then outputting to a printer to make a etch mask.
i am not sure what method to use to make the mask and how to apply to
the copper using a printer ..
any ideas ?
how long to imerse in the ferric chloride or similar solution?
say to etch of 1/16" of metal.

thanks