Homebrew PCBs

On Sun, 2006-12-31 at 14:13 +0000, Paul wrote:
> Which is the best paper to use for the toner process?.
> Which is the best etchant?

This could be a little like asking what's the best programming language,
best text editor, best religion, best political party... It's very much
geared to personal experience.

I personally tried the 'time magazine' glossy paper approach advocated
by many. The toner stuck ok after 10 passes through the laminator, but
there was some blurring in the artwork, and it ended up looking slightly
hand-drawn. It would play havoc if I'd been using SMD components, or
copper pours.

I tried the 'press'n'peel' commercial blue film, but even after many
passes through the laminator, it still wasn't giving up its toner.

Finally I tried inkjet gloss photo paper - 175gsm gloss/satin finish,
made by www.celcast.com.au, code IJ121. This paper gave up its toner
quite well, although I still needed to soak/rub it off. Also, the
transfer left a high-fidelity image. With the lack of distortion, I can
confidently use this paper for boards with SMDs and copper pours.

As for etchant - have only tried FeCl. I use 2 disposable food punnets
(the smallest size - smaller than a block of butter). I half-fill one
with boiling water, then put the second one in over the top, and put in
the board (copper side up) and some FeCl, then gently move the top
punnet from side to side so the board keeps hitting each end.

This takes about 15 minutes to eat off all the exposed copper. Perfect
results. Also, you can save the used FeCl solution in a spare bottle (eg
a small vitamin bottle), and re-use it for 5 or more boards.

Hope this helps

Cheers
David

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