Homebrew PCBs

On Fri, 14 Jul 2006 16:05:03 +0200, lcdpublishing  
<lcdpublishing@...m> wrote:

> Hi ROyce.
> Don't know yet.  I am still trying to find a regulator that I can use
> for this and don't have time for the "Search" yet.  I am hoping this
> weekend I will get some time to finish it up.
> I did notice though an interesting thing (I am only using water at the
> moment).  There does seem to be a bias as to how the water flows and
> circulates in the tank.
> For example, if there are more bubbles on the left side, the flow of
> water is in a circular, clockwise rotation.  This draws the bubbles
> from the right bottom and pulls them towards the left side as they
> rise up.  What I am not sure of is if the bubbles actually do
> the "Scrubbing" or is the "Scubbing" simply a function of the flow of
> etchant.
> If the bubbles are doing something, I will be getting some uneven
> etching. I am going to try and modify the baffle a bit so that the
> flow is back to front as opposed to left to right.  I believe this
> would even out the etching.


I see the same here.
When i switch the pump on the bubbler will fill from the left, so will  
bubble there first, causing a circuiar current to start.
This is sustained unless i stop the pump, wait for the current to slow,  
and start the pump again (now with a bubbler already filled with air).

There's still such currents then, but not as extreme.

I guess nothing can be done, it will be impossible to get it totally even.

ST