Homebrew PCBs

On Fri, 15 Apr 2005 18:09:02 -0400, Alan King <alan@...> wrote:

>
>    Nope, would take some tests.  Just a flat plate in the bottom corner  
> leaning
> in at an angle should give an idea.  Just occurred to me off the top of  
> my head
> that the bubbles are giving less action from spreading out horizontally  
> and
> joining together as they rise when I read your last message.  A wedge  
> pushing
> them back towards the board should do a lot for it.


Well, while it sounds like a good idea, it needn't necessarily really work  
;-) .

I think the bubbles will not stay attached to the board, unless you can  
get that wedge very, very close.
Which might actually work, like making the gap smaller than bubble  
diameter. the flow of etchant is pretty high from the bubbles so it should  
stay fresh.


BUT this needs experimenting, and i can not just make the walls of the new  
tank sloped a guessed angle.
I think it is easier to make the tank straight and insert plastic plates  
at a later time. It could be like a upside-down funnel shape at the bottom  
of the board, herding all bubbles through a small gap between pcb and the  
bubble-guide.

A possible problem i see with this is that one would need a very precise  
board holder, if the board is not centered precisely it will cause trouble.

ST