Homebrew PCBs

>From: "Stefan Trethan" <stefan_trethan@...>
>Reply-To: Homebrew_PCBs@yahoogroups.com
>To: Homebrew_PCBs@yahoogroups.com
>Subject: [Homebrew_PCBs] bubbler system
>Date: Tue, 07 Dec 2004 16:09:06 +0100
>
>
>
>Hi everyone.
>
>I decided i do need some sort of agitation for my etcher.
>i tried moving the board, it works well but tends to shake to board loose
>of the
>holder.
>The etching takes too long, and it is very uneven because the spent
>etchant sinks down.
>
>So i went to a aquarium shop for a air pump.
>got one for 10eur, took it apart and found the pumping part is made
>entirely of rubber
>and plastic (only one M3 screw needs relacement with nylon or a protective
>silicone coat).
>This means for me i can scoop up the air from under the cover of the etch
>tank, releasing no corrosive
>mist into the room, or at least much less.
>
>I got a bubble-stone with it, but it is just a small (2cm) ceramic ball,
>no good for even
>distribution of bubbles.
>They don't have other bubbling stones, i believe i remember reading about
>"fritted glass" or something
>here?

I've got a rectangular stone, about 10 cm long. Haven't tried it with an air 
pump, though. I find that contnuous manual agitation of the etchant 
container worrks very well, and only takes 10 minutes or so.

Leon