Homebrew PCBs

Adam Seychell wrote:
> Does anyone know if those flexible air bubble hoses used for fish tanks 
> are any good for ferric or CuCl etch tanks ?
> 
> see,  http://store1.yimg.com/I/animalworldnetwork_1863_24150004
> 
> I know they have a lead metal insert that gives them ability to be 
> shaped, and provides the weight. If this lead is not covered in plastic 
> then it will not stand up to these etchants after a while. I've just 
> ordered some to try, as I'm having bad luck with other "air stones" sold 
> at aquarium stores.
> 
> I've tried garden "soaker" hose, but the consistency of air release is 
> very poor across its length. Its not designed for fish tanks.
> 
> I've also tried a series of 1mm holes in PVC tube, but the air bubbles 
> are too large causing very low back pressure. Again this gives very 
> non-uniform bubbling across its length. I found the air volume needed to 
> get good back pressure way too high (tested with water tank and a 
> compressor).
> 
> So I've come to conclusion you need lots of evenly distributed small 
> bubbles to get uniform agitation.

How about a block of porous carbon or charcoal? Glue a half-section
of pvc pipe along its length for the air-supply.

Another way is to drill 10mm holes in the pvc pipe and plug them
with porous carbon "corks".