Dwayne,
Did you find the Ammonium Persulfate to have a short life for production
work? I did not use it because of the life of the mixture. Was just
wondering about your experience with it.
-Mike
----- Original Message -----
From: "Dwayne Reid" <dwayner@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, April 26, 2003 10:49 AM
Subject: Re: [Homebrew_PCBs] Homemade PCB holders for etcher
> At 09:18 PM 4/14/03 -0700, luther m stroud wrote:
> >I tried verticle etch with cucl and it was't even faster near the bubbles
> >from the bottom that at the top . stainless steel may not last in the
> >etchant .
>
> The PCB holder arrangement I described has been working well for at least
> 15 years - that is about the age of the holders I described. However, I
> use ammonium persulphate catalyzed with sulfuric acid as my etch
solution -
> clean and effective. My etch tank is welded stainless steel, as is the
> immersion heater used to heat the etchant - both of these have been in
> regular use for about 20 years. We used to just hang the boards in the
> etcher before I made the holders.
>
> Vertical bubble etch is somewhat slower than a spray etcher but there is a
> lot less mess and it was cheap to build. This was a very important
> consideration back when we built our PCB etch system.
>
> The air source is a very compact blower (something like a vacuum cleaner
> motor) obtained from a local surplus outlet (Princess Auto) years ago.
The
> sparging tubes are drilled PVC - 2 tubes that form a "U" in the bottom of
> the tank.
>
> I've been told that the reason bubble etch works so well with ammonium
> persulphate is the constant agitation and the continuous addition of
oxygen
> to the etch solution. We pretty much followed Clyde Coombs PCB Handbook
> and it just works.
>
> dwayne
>
> --
> Dwayne Reid <dwayner@...>
> Trinity Electronics Systems Ltd Edmonton, AB, CANADA
> (780) 489-3199 voice (780) 487-6397 fax
>
> Celebrating 19 years of Engineering Innovation (1984 - 2003)
> .-. .-. .-. .-. .-. .-. .-. .-. .-. .-
> `-' `-' `-' `-' `-' `-' `-' `-' `-'
> Do NOT send unsolicited commercial email to this email address.
> This message neither grants consent to receive unsolicited
> commercial email nor is intended to solicit commercial email.
>
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>