Hi Stefan,
You can make holes in a plastic tube but they need to be very small. I
used a small pin that I heated up with a candle flame. If you use the
pin cold the hole tends to seal up as soon as you remove the pin. You
don't need many holes. If I remember correctly my system worked best
with about 5 holes in a 180mm length of pipe. I am working from memory
here because my tank now has the holes built in.
You need a pump with a reasonable flow rate if you go this route
otherwise you may find that air only comes out of one half of the tube.
> Another thing is, do you think those air pups can pump liquids?
No they won't. They rely on sprung magnet that is alternately attacted
to and repelled from an AC electromagnet. The weight of the magnet and
spring are designed so they resonate at mains frequency. Any quantity of
liquid in the pump will damp out any movement and it will stop working.
I found this out when I had some etchant syphon back into the pump
overnight.
Les
Stefan Trethan wrote:
>
> 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?
> What about making holes in a hose? would that cause too-big bubbles, and
> too few?
>
> Another thing is, do you think those air pups can pump liquids?
> alternatively to pumping air i might
> just pump the etchant around. I will test that with water. Other pumps
> (centrifugal for aquarium filters)
> have a magnet exposed to the liquid, and a metal shaft (expensive ones
> have a ceramic shaft, or so they
> say). Would the magnet be attacked by etchant? it is a hard "black" type,
> not a neodymium magnet.
> Maybe the magnet could be painted or something...
>
> While we are at pumps, i learned something interesting: for CO2 feed
> systems the aquarium guys use
> reactors. that is a cylinder where the water is pumped downwards, while
> the co2 gas rises against the current.
> they place obstacles into this cylinder too.
> If it is adjusted correct almost no CO2 reaches the top, all is solved in
> the water. this might be an effective setup for air-regenerating CuCl.
>
> thanks for any hints about that bubbler stuff (but suppliers in the US are
> not of much use).
>
> ST
>
>
>
>
>
>
>
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
>