In article , "Upscale" wrote:

Ok, I picked up a roll of the yellow tape today, but reading the
instructions on the back a little more closely, I'm not sure if I should use
it or if it's usable for my 150 psi compressor.

Here's what I got:

It's certainly yellow. The front description states "Gasline thread seal
tape".
On the back in finer print it states "Do not use on flared threads".
And then the following blurb:
"Got use in assemblies handling gasoline, petroleum oils, propane, butane
and natural gas not exceeding 100 psig".

I'm guessing that 100 psig is gallons volume,

It's a pressure measurement. "psig" = "pounds per square inch guage" as
opposed to pounds per square inch absolute. To illustrate the difference,
which is of interest only to scientists, normal atmospheric pressure is 14.7
psi absolute, at which pressure a guage will read zero. For practical
purposes, "psi" and "psig" are freely interchangeable.

so I'm not so concerned there,
but the threads on the brass fittings *are* flared which to me means that
the circumference gets gradually larger on the male part of the fittings.

That would be a tapered thread. Gas-line pipe (black steel) uses tapered
threads, which actually slightly expand the fitting when the pipe is seated
properly, making a very tight seal. (If you've ever heard that gas-line
fittings should not be reused after a joint is disassembled, that's why.)

Are you sure it says "flared" and not "flare"? I could understand the latter,
in reference to flare fittings (which are used on gas-line *tubing*), but not
the former.

I
guess I'll use it anyway since the only realistic problem I might get if
there is one is the hiss of a little air.

Go ahead and use it. The warnings are all about avoiding any leaks of
dangerous substances such as "gasoline, petroleum oils, ... natural gas".
As you've already realized, since you're only using it for air, even if it
does leak that presents no danger.