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Subject: RE: [Homebrew_PCBs] Heated etchant rocks!

From: "Tony Smith" <ajsmith@...>
Date: 2007-05-19

> I have seen three with stirrers, usually the larger ones have
> them but i
> also have a very small very early oven with one.
>
> IMO the superior method over the turntable, but a bit more tricky
> technically.
> One i looked into used a plastic ball bearing (just like
> metal only clear
> balls). I suspect the metal ball bearing would cause arcing
> and wouldn't
> work. The stirrer was powered by the cooling airflow (so the
> friction
> needs to be low).
>
> ST


The small one I saw had the stirrer run off the airflow. I suppose that
would clog up the bearing eventually. Makes sense that they'd work better,
fewer cold spots.

A quick rummage around Google shows stirrers are still around. Some models
have them in the sides as well. These are commercial ones, and are driven
by motors (with belts).

Tony