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Subject: RE: [Homebrew_PCBs] Muriatic Acid and Peroxide Brew

From: "Bertho Boman" <boman01@...>
Date: 2008-07-02

You have a lot of patience!



I have not etched any PCBs for a few years but I used to do quick single
sided ones for prototypes and fixtures.

Smaller boards I used to etch in round glass dish on a hotplate with a
magnetic stirrer for fast agitation. With the agitation and hot FeCl it
took just a few minutes to do a board. I turned the board upside down and
held it in place with a suction cup.



For bigger boards I used a rocker with hot FeCl. I started to build a
spray etcher but got too busy to finish it.



To get good results I think it is important to have lots of agitation to
avoid the etchant to locally saturate.

Bertho



From: DJ Delorie Sent: Tuesday, July 01, 2008 20:16
-àsinip
I did a board today and it took 40 minutes. At least, I remembered to
go check it at 40 minutes and it was done ;-) I also positioned it so
that the air bubbles actually hit the board, not just went past it.

Actually, my problems over the weekend were due to ∗over∗ etching.
I'm still experimenting with the photomask. So far I've learned to
match up line/space rules across a panel so that the etch times match.
Maybe I'll cut up the panel after exposure so I can etch them
individually. Small traces with big spaces were etched away while
waiting for a board with small spaces to etch. It never did, even
after 2 hours. Maybe floating it over FeCl would result in a more
consistent etch.



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