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Subject: Re: [Homebrew_PCBs] air sparger for cupric chloride etchant and supplies

From: Adam Seychell <adam_seychell@...>
Date: 2003-04-01

That's good you found a place selling that stuff, sometimes these
plastics are hard to locate. Stay with PVC , because its the only
plastic you can easily glue and bend with a hot air.

I've built several air spargers systems over years for aerating
tanks. The 1 mm diameter holes in PVC ridged pipe works ok if you
got a big air supply. It gives you large bubbles and they can
tend to flow into a stream on one side of the tank. Its more
effective to have lots of fine bubbles, as the liquid/air surface
area is increased and tends to produce more uniform sparging. I
use some porous garden irrigation hose. Its usually available in
say 20 meter rolls with a 12 mm ID. The remaining 19.5 meters can
be used on a garden :).

DIY irrigation supplies also make good places to buy chemical
resistant plumbing. Be careful, some fittings are made from nylon
and won't last in HCl. Burn a small part of the plastic and it if
bubbles and fizzles and the smoke is very irritating then its
nylon. If the plastic simply melts when burning and maybe even
drips on the ground then you have polypropylene fittings.
Polyethylene burns similar to polypropylene except the smoke
smells like candle wax smoke.

The more air the better, so buy the largest aquarium air pump you
can afford. I though of using a sewerage treatment aeration
pump, but they are $$$.

grantfair2001 wrote:
> I spent several hours looking for an inexpensive source of schedule 80
> 1/4" PVC pipe and fittings to make the air "sparger" outlined on the
> "Think and Tinker" website.
>
> I was pleasantly surprised with my experience with this website:
>
> http://www.usplastic.com
>
> They sold me 10 feet of 1/4" schedule 80 pipe, two end caps, two 90
> degree elbows and one tee, for $11.97. There was no shipping fee. This
> is much cheaper than several other sources I found on the 'net.
>
> I thought this might be on interest to list members wanting to use
> cupric chloride etchant. (Other than being a happy customer I have no
> connection with US Plastics.)
>
> Grant
>
>
>
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