Homebrew PCBs

Stefan Trethan wrote:
> On Wed, 14 Sep 2005 03:14:29 +0200, Adam Seychell  
> <a_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.
> 
> 
> 
> I have one very identical to the one in the picture, only black.
> I took the lead wire out, and then glued it to a plastic stick which i  
> wedged into the tank with hot melt glue.
> The bubbling holes are in two rows on one side on my hose, and i pointed  
> them up.
> 
> 
> It's still not entirely uniform, but it's OK now, and it would get even  
> better with more pump power (have only 110 l/h on a 40cm hose).
> The smaller the bubbles, the more there are, and more importantly the more  
> they will travel sideways in a random manner before reacing the top (large  
> ones are more buoyant and go up the same path each time).
> 
> 
> Holds up well in CuCl.
> 

Thanks for that. I'll try removing the lead wire or put a piece of 
heatshrink tube over it.


I know what your saying about the more air delivery the better the 
uniformity. I've had a few aquarium pumps over the years, and you really 
need the "larger" type. I also ordered a piston type pump shown  here;

http://avk.com.au/catalog/product_info.php?products_id=77&osCsid=b52294d9a298538f4bd203a7dbe86f28

manufacturer's site:
http://www.resun-china.com/web/Eng/ELECTROMAGNETICPUMPS.htm


At 20 L/minute (1200 L/hour) these piston pumps are cheap compared to 
diaphragm types. But apparently noisy too, so forget using it on the 
bedroom fish tank.  I think for good bubble etching, air pumps should be 
  >= 500 L/h.