Stefan Trethan wrote:
> rotatig. Sometimes it oscillates "pulsing" the spray pressure, at other
> times it doesn't. It is running way too loud and i'm sick of seeing it to
> be honest. I do not see a point where the uniformity will be better than
> with a bubbler in a somewhat reasonable timeframe and the eventual
> increase in etching speed is long eaten up by construction time.
Hadn't been following lately, sure there isn't more to the commercial
systems? What's the diameter of the tube? Even 10K RPM isn't much if the
diameter is small. And water has a strong adhesion force, it could be very
important that the tube is the right type of plastic so it's not sticking as
it's coming out of the holes. Still seems it would be problematic. Also is it
pressurized from the other end in commercial unit? Etchant in a small closed
tank, and pressurized with say a $10 car tire pump, basically a lower pressure
pressure washer.
> I must draw a line somewhere how far i'm prepared to take this, and i have
> reached it i think.
> I would much rather spend my time actually making PCBs (especially
> following up on the silicone paper).
>
> My plan now is to lay this project to rest, and use the existing materials
> to build a bigger, better bubble-tank with all the flaws of the old one
> corrected. The slightly uneven etch and longer times are something i must
> live with i fear.
>
How are your bubble etches uneven? More finer bubbles should make things
fairly even in a local sense, if it's more etched at the top than bottom or vise
versa then use more bubbles and slope the side of the tank away from or toward
the board to even things out.
Don't need one myself, but I'm thinking one of the long fine bubble aerator
tubes for fish tanks and a sloped tank side to even things out against a
vertical board should come out fairly even. But bubbles do only travel one
direction.
Not sure that's even needed. Use a rigid frame for the board, on a floating
suspension over the tank. Stick a medium sized massager vibrator motor on the
frame and see if that doesn't work. May need a small amount of pumped
circulation for best effect, but a vibrating board should do fairly well just by
itself.
Alan