Homebrew PCBs

It looks like the Sweetwater air diffusers might be best for the job,
in that they last forever in an acidic environment, according to the
manufacturer. There is a Canadian seller but they are on the west
coast so it will take a while. That firm also sells air diffuser hose,
which is much cheaper (C$2.00/ft) than the Sweetwater airstone (which
you pointed out), which is $31 for one 12" stone. Click on 'diffuser
hose' at:

http://www.direct.ca/dynamicaqua/diffusers.html

It is rubber and polyethylene. Adam, or other group members - any idea
how that combination would hold up to an acid bath?

In the meantime, on the basis of your experience, Adam, I decided
against putting pin holes in the hose. Instead I drilled very fine
holes in an 18" piece of 1/4" ID schedule 40 PVC pipe, plugged one
end, and stuck the air hose on the other end. The bubbles are finer
than the sparger makes, but not tiny. Not bad for 1/2 an hour of
drilling, though.

I have had the sparger on since I removed the mushy airstone. But the
etchant is still a coca cola brown in color. Condensate (or splash) on
the inside lid is quite green, though. Anyway, finer bubbles would
seem to be the key. I will see how the new test aerator does, but I
think I will at least buy some of the aeration hose.

It's taking longer than I hoped, but when it is ready, I have a lot of
etchant which will make it easy to etch quickly and keep the etchant
ready to go - I hope.

Grant

 
--- In Homebrew_PCBs@yahoogroups.com, Adam Seychell
<adam_seychell@y...> wrote:
> I once tried pin holes in PVC tube, but the bubbles always come 
> out big compared to air stones. I think they air needs to pass 
> through all those small cavities for it to make small bubbles.
> When experimenting its always a good idea to use a bucket of 
> water first.
> 
> Adam