Homebrew PCBs

A flexible bubbler hose works OK for me.
The bubbles are not entirely uniform in density, but at least they are  
small.

It is a black foam hose, with two rows of tiny holes cut in the outside  
with something that must be like a pizza wheel. The hose looks identical  
in make to the black soft foam isolation you get for refrigerant systems,  
i expect is is from such a source only a very small diameter (maybe 1.5cm).
There's a lead wire inside to weigh it down -> remove.


I'd like to have a even more uniform bubbler since i still get streaks on  
the PCB that etch faster, but i haven't found one yet.


BTW what a coincidence - my tank sprung a leak today! Luckily the plastic  
safety container the tank sits in does it's job well. I drained all the  
etchant into bottles and found it leaked in the same place again. The  
etchant seeps through the gap between the edge of a panel and the bottom  
plate which i must not have sealed properly. I had already put silicone  
all the way around the outside of this joint to seal it up when it leaked  
"back then", but i didn't do a terribly good job and such things tend to  
come back and haunt you. So i carefully cut away the old silicone there  
and re-did it properly. Will try tomorrow if it is OK now.

So, if you build a tank, do put silicone right on the edge of each panel  
so this gap is sealed all the way. Check if it is sealed by looking from  
the other side, i did not do that...
The aquarium people manage to hold together the whole tank by gluing only  
at that very edge, i prefer to let one panel protrude so i can put i nice  
bead on the outside of the tank. I glued the first tank outside and  
inside, but it is tricky to get into a narrow tank so i didn't do that  
with this one. It shouldn't be needed when the rest is done properly.

And do make sure the whole thing sits in a larger vessel that is reliable,  
VERY reliable.

ST


On Tue, 11 Jul 2006 17:58:53 +0200, lcdpublishing  
<lcdpublishing@...> wrote:

> Hi Guys,
> I am working on a new etching tank for Ferric Chloride.  I was using
> two bubble stones for aquariums, one clogged pretty quickly and the
> second one didn't last all that long.
> So, I figured I would take a sheet of PCB board and drill a bunch of
> holes in it as a baffle.  The I would run an air hose through it and I
> would have lot's of tiny bubbles coming up.  Nope, I got big bubbles
> out of a couple of the holes.  I started out with .020" diameter
> holes, then tried .035, then .045" and finally .055" holes. Not
> working good at all.
> So, I am stumped now and am wondering what you guys are using to get
> better distribution of your air bubbles.
> Chris