In article , Jack Stein wrote:


Upscale wrote:
I've just picked up a new portable compressor, hose and an array of
fittings
~ all connections will be brass to brass. Do I need plumber's tape for
these
fittings or should I be fine with just the brass to brass? I was wondering
what others have done?

Jack Stein wrote:
I don't see any need for tape or dope on compression fittings.

Doug Miller wrote:
Compressed air fittings are not the same as compression fittings.

Brass compression fittings certainly are common compressed air fittings?

??

Non-compression fittings need tape or dope regardless of what they are
made of?

Tape or dope should be used for all fittings for ease of proper assembly.

Nope. Tape or dope is not needed at all for brass compression fittings
commonly used in air lines, water lines etc.

Compression fittings are not at all common on air lines in my (admittedly
limited) experience.

The joint won't seal unless it's tight, and the tape or dope reduces friction,
making it easier to get the joint tight. And it's pretty much mandatory for
anything that might be disassembled later.

I don't agree, brass compression fittings can easily be overtightened,
and dope/tape could facilitate that. Also, tape/dope could contaminate
the compression fitting resulting in leakage. Other than that, using
dope/tape on a brass compression fitting is pretty much meaningless. If
the oval ring in a compression fitting leaks, all the pipe dope or tape
in the world will not help it, and a new ring/fitting is needed.

Where have you seen air lines with compression rings in the fittings?

Tape/Dope should always be used on non-compression fitting, for the
reasons you site. The original poster said only brass to brass, and
didn't specify compression or non compression fittings.