Might use a pump up type sprayer. All you want to do is keep the surface wet
with Alodine for 5 to 10 minutes. You could even have it horizontal and do
one side at a time.

"Veeduber" wrote in message
...

Anybody have any favorite techniques for doing big pieces? I've not been
able to find any alodyne tanks locally, and I've only got a gallon each
of aluminum cleaner (phosphoric acid) and alodyne. The option is to

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Dear Ed,

I think it will take about two gallos of each.

The process involves plastic or epoxy-coated rain guttering as a lower
trough,
a series of spray nozzles & black plastic tubing along the upper edge, a
submersible pump, two or three A-frames to support the rain gutter and
some
5-mil plastic sheet. The rear plastic panel is fixed in place, the front
part
is suspended like a curtain, hangs into the rain gutter.

You do one side at a time.

Lift/raise the curtain, put the panel or sheet into the trough, lower the
curtain & tuck it in then turn on the pump.

Depending on temperature and the flow-rate of the pump (and output of the
nozzles... measure the 'out-fall' where the rain gutter delivers the
solution
back to the sump), average time per side was about 4 minutes.

Water-rinse is done with a HOSE. Just get the plastic out of there,
divert the
out-fall and walk down the length of the panel, blasting away.

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It isn't very hi-tek and if doing 4x12's it helps if you make up some
handling
frames -- things with those vacuum cups for working with glass -- that
will
allow you to position & flip a panel without chopping off your foot.

The idea is to protect the metal quickly and at least cost, usually
because it
will have to go into outside storage. This method is sorta gross but it
works.

You can salvage the spray heads & tubing if you wish, use it in your
garden.
The pump is usually trashed after pumping phosphoric for a couple of hours
(but
maybe not... had a little all-plastic thingee that didn't seem to mind the
chemicals at all).

This isn't a new idea, other than the addition of the pump & sprayers.
They
used to use a rack like this at NAS North Island, couple of guys, all
suited up
in rubber boots & aprons, scrubbing down panels with big fuzzy brushes.
The
gutter was a piece of black sewer pipe cut in half, sloped so they could
recover/reuse most of their solution. Seemed like a good idea.

-R.S.Hoover