[Shop-talk] setting up compressed air lines

[Randall]

> wondering if there was some formula/trick to determining
> where to cut a pipe
> so the length ends up correct,

For an elbow or tee, I just assume that the centerline of the side pipe will
wind up about 1/4" (for 3/4" pipe) beyond the cut.  It's not exact, but
close enough for my purposes.

The exact relationship depends on how far down the pipe you run the die.  So
pick a reference point, and cut threads to that reference point.  Then do a
trial assembly, after marking the pipe a known distance from the cut end.
Of course there may still be some small variation, because the fittings
aren't always tapped to the same depth either.

Loctite makes an anaerobic sealant for pipe threads, which seems to work
somewhat better than the old 'Teflon' pipe dope (which is really just a
lubricant so you can tighten the threads until they deform into each other).

Sorry, no help on the rust.  I just used brass at the water collection
points.

-- Randall