Homebrew PCBs

On Thu, 10 Mar 2005 08:08:45 +1100, Adam Seychell  
<a_seychell@...> wrote:

>
> I've had the same experience. Nylon is the culprit. I've heard before
> that big bubbles produce more a agitation. This is where you need more
> air than conventional home fish tank air pump. I've looked around for
> such pumps and found some hydroponic stores sell large pumps, and then
> there are places that sell pumps for outdoor fish ponds and even home
> sewage treatment. There are high volume air pumps that are not too
> expensive. These cheaper high volume pumps are a bit louder and shorter
> life span, but that is unimportant for etching.
> Adam


I just wrote a series of questions to ebay guys selling interesting  
bubblers, asking which material they are and to please describe it as best  
as they can if unsure.
As said the round one is no nylon, it seems like ceramic or something.
It looks just like the round grinding bit you get for drilling machines,  
with about 2cm diameter, and a seam in the middle from forming. It  
basically looks like blue quartz sand somehow magically held together.
If you'd glue in a shaft instead of the tube for the hose i'd have taken  
it as a grinding bit with no second thought.

I can throw that one in the CuCl just for fun to see if that sort of  
material holds up. I've already seen a bubbler that seems like that  
material but 25cm long.


I fear it was not a good idea to go for the cheapest and smallest air  
pump. I want to run it closed loop and i am a bit reluctant to spend much  
money for a pump which might have metal components in the air path which i  
can not use. I'd rather buy a second small pump and connect one each end  
of the stone.

Have you looked at think/tinker? they suggest drilling a larger hole, but  
not all the way through the tube-wall, to form a small space where the air  
collects before breaking free (which allows a small pump to make big  
bubbles).
In my small tank i can't fit a big tube with thick walls, but i think i  
could make the same effect by using electrical wiring tubing and a hot,  
blunt rod to make indentations, say 5mmdia and 5mm deep, and in the center  
drill a tiny hole.


Also, as it is now the airstream created huge eddy currents, rising in the  
middle of the tank and dropping at the outer sections. This current draws  
all air in to an extent where the air from the outermost nozzles is  
deflected to rise within the center half of the tank. Luckily most boards  
fit in that space but it might be a problem in the future.
I plan to make a wider tank when i have a better bubbler, which might  
solve that problem (or not).


ST