Ig,

Air piping is discussed here on a regular basis. Look in the archives.
Well, since google frigged them up, try to look in the archives, anyway.

To sum up: don't use plastic unless it is specifically rated for use
with compressed gasses, and most of what you'll find to buy is not. PVC
is not suitable (cue the people who have PVC piping and never had a
problem with it - which they won't, until it shatters one day, and they
do).

I'm in the copper camp (cue the "copper is unsafe, but we can't quite
explain how, but we say it is, so it must be" people).

There's also a black iron pipe and a galvanized iron pipe camp, mostly
among people who already bought pipe dies and need something to use them
on, as well as persons who are prone to believe people who say something
is unsafe, but can't explain how (cue the copper camp noting rust and
zinc in your air, and large commercial copper installations).

Finally, there's the "100 feet of rubber airhose" camp.

Pick one, and enjoy. Use a section of flexible hose to connect the
compressor to any sort of fixed piping (for vibration isolation), and
arrange so that water will drain down to a place (or places) where it
can be removed, while taking air drops from the top of the pipe so that
they are less prone to get water in them (put a drain leg at the bottom
of each air drop, anyway). That is, use a tee pointing up and 2 ells to
point down, rather than a tee pointing down, to get air down from a line
high on the wall.

--
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