Homebrew PCBs

Stefan Trethan wrote:
> The whole thing meaning, in CuCl the foam doesn't circulate because the  
> bubbles only go up, but it isn't a problem as with more air the same  
> effect can be achieved.

   It'll still be making circulation, but maybe not as good a rate..



> What i do not know is if bigger or smaller bubbles are better.  
> think/tinker is sure big bubbles are good, 'cause small bubbles are not  
> causing enough scrubbing action. OTOH i have tried big bubbles, and it is  
> hard to get them evenly distributed over the board and they tend to form  
> vertical streaks on the board that are 2 to 3 times faster etched than  
> other places. I will rather have smaller bubbles, and slightly longer  
> etch, if it is even.
> 


   Unconstrained, bigger probably is better, causing more direct action in the 
liquid as the bubble moves up.  But with more smaller bubbles and being kept 
toward the board I doubt you'd see much difference, and of course the smaller 
should be more even.  There are 8-10 inch long 1/4 inch round green tube fish 
aerators that put out lots of bubbles, that's what I'm thinking of.  Hard to 
find a pic, don't know the brand name and you get too much other stuff on a net 
search.  May just get a couple for trying later if I go out and send a picture.

Alan