Has anyone tried this method for chemical machining. I am making some encoder disks for the digital DC servos I am building and was going to use conventional dip FeCl bath. Is the undercutting any less?
--- On Fri, 8/14/09, DJ Delorie <dj@...> wrote:
From: DJ Delorie <dj@...>
Subject: Re: [Homebrew_PCBs] instructables 1 min PC etch using sponge & FeCl
To: Homebrew_PCBs@yahoogroups.com
Date: Friday, August 14, 2009, 4:17 PM
William Alford <walford@dbtech. net> writes:
> http://www.instruct ables.com/ id/Sponge- Ferric-Chloride- Method-Etch- Circuit-Bo/
Yup, this is the standard Pulsar method (as noted in the
instructable) , and the whole reason behind the Green TRF. With
preheated FeCl, a sponge, and 1/2oz copper, I can etch a board in
about 45 seconds. You can also focus on underetched parts so you
don't have to overetch elsewhere to get good results.
My way was to half fill a 1 gal bucket with hot tap water, slightly
loosen the cap on the FeCl bottle (to allow for air expansion), and
put the bottle in the bucket. By the time I'm done putting the resist
on, the FeCl is hot, and I pour it into my usual etch tray. I then
hold the board over the tray and dip the sponge into the etchant, wipe
a few times, dip, wipe (not scrub!), etc. The dipping replaces the
used etchant with fresh etchant, and keeps the sponge warm.
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