Homebrew PCBs

Gee, that site really does a lot of good. The guy hates Americans and it is
not posted in English. Doubt if I would trust sending "my" money there.
-Mike

----- Original Message -----
From: "Markus Zingg" <m.zingg@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, April 23, 2003 2:17 AM
Subject: Re: [Homebrew_PCBs] Stirring or pumping etchant


> Hi Group
>
> This is my first time post here, so please forgive me in case this is
> already known. However, there is a small german company selling very
> low priced spray etchers which are not that bad. There is a model that
> etches one side, and also one that etches two sides at once. However,
> the single sided model can also be used for double sided PCB's by
> simply turning the PCB once one side is etched. The signle sided one
> goes for ~117 Euro (about the same in USD), the double sided one goes
> for ~178 Euro. I have the single sided one and I'm pretty satisfied
> with the results. The advantage of this etcher is that the device is
> "always" ready, there is no mess with etchant since it's a closed box
> and etching goes fairly quick also (3 minutes per side). The principle
> is simple. There is a rotating tube that delves on the bottom of the
> box into the etchant. Since the tube is having fine holes, the etchant
> is forced out of these holes due to the rotational speed of the tube,
> this results in a fine spray of etchant going over the PCB. Even
> though the device is simple I would find it hard to build the same
> device on my own for the same price. Let me stress that I'm not at all
> related to this firm. I'm simply a happy user of one of their
> products.
>
> Here's the link, search for "Spr\ufffdh\ufffdtzer".
>
> http://www.radixgmbh.de
>
> A word of warning though. The guy running this site aparently is
> having a problem with the foreign politics of the US governement. Let
> me stress that because of this I really thought twice to publish this
> link here but then the etcher is simply too good to be ignored.
>
> Markus
>
> >Some ideas I haven't tried:
> >
> >Use a stainless steel stirrer such as is used for making milk shakes.
> >
> >Make some stirrer vanes out of suitable plastic, drive them with small DC
> >motors (so you can adjust speed by adjusting the voltage).
> >
> >Make a centrifugal pump out of plastic.  It doesn't have to be terribly
> >efficient, just needs to direct a stream of etchant across the board to
be
> >etched.
> >
> >Use an oscillating room fan, or a windshield wiper mechanism to move the
> >board around in the etchant solution.
> >
> >Chemical supply houses have a combination hotplate/stirrer.  The stirrer
> >works by having a rotating magnet underneath the beaker, and inside the
> >beaker you put another magnet that is coated with some inert material.
You
> >might be able to use a "cow magnet" as the coated magnet.  These are fed
to
> >cows to attract iron nails and stuff in the cow's digestive system and
get
> >them out of the system.  (That's no bull :-)  I just called a veterinary
> >supply company and they sell a 2-inch coated cow magnet for $2.65.)
> >
> >You might not even need the cow magnet.  Since the etchant is conductive,
it
> >will try to stay stationary with respect to any magnetic field.  So, if
you
> >rotate a strong magnet adjacent to the tank, the solution may rotate in
the
> >same direction.  This is the principle that makes induction motors work.
> >
> >Use a peristaltic pump, such as from scrapped medical equipment.
> >
> >Cheers,
> >- Jan
> >
> >
> >
> >
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> >
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> >
> >
> >
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>
>
>
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