Homebrew PCBs

What is the best method to etch with a bubble tank. I have a 4 liter tank with a bubbler glued in the middle. Where do you place your board to be etched? I have tried in the path of the bubbles (vertical), caused under etching, and placed the board on the side of the tank(vertical), takes longer and good results so far. Should I place my bubble stick on one side and board on the other? Should the board be held vertical in the the bubbles or vertical on the side or perpendicular to the bubble flow?

Brian.

Brian wrote:
> What is the best method to etch with a bubble tank. I have a 4 liter tank with a bubbler glued in the middle. Where do you place your board to be etched? I have tried in the path of the bubbles (vertical), caused under etching, and placed the board on the side of the tank(vertical), takes longer and good results so far. Should I place my bubble stick on one side and board on the other? Should the board be held vertical in the the bubbles or vertical on the side or perpendicular to the bubble flow?
> 
> Brian.
> 
> 
I've done bit of experimenting with bubble tanks. What I found is that 
if the tank is too wide then bubbles will tend to converge into streams 
causing the solution to cycle downward in paths that are absent of 
bubbles. The result is poor agitation uniformity.

The bubbles need to flow randomly up the entire height of the tank. This 
can be done by distributing air over the whole base area of the tank and 
keeping the tank narrow. If the bubble density is high enough then there 
is little room to form paths of downward liquid flow (that compensate 
rising liquid dragged by the bubbles).

Adam