To get this slightly back on topic, check out this link:
http://www.onboardair.com/  Remember, David wanted to know if he could use a
AC compressor to air up his tires after going off-highway and to use air
tools to swap his diggers to his road tread.  Not to make motorcycle tires
bombs...

Sure would impress the guys to whip out a hose after being off road to air
up.  Not to say that blowing up a tire with a chuffer (spark plug valve)
isn't cool, it's just more McGuyver cool as opposed to James Bond cool...

Original Post.

 I am about to install an AC compressor into my Double Cab - funny thing is
there is no AC - it sort of comes with the motor!  I am thinking as long as
the electric clutch isn't engaged and I plug the compressor line openings
things should be OK.  Then I get thinking to myself - I wonder how good
these are at compressing air???  The plan is to put an expired propane tank
in the 'treasure chest' that is under the bed of the Double Cab.  With this,
I would have the compressor fill it with 125PSI of air so I can do things
like air down my tires and fill them back up again with out a hand pump or
be able to use air tools to remove street tires for off-road tires.   Is it
good to compress air with an AC compressor or am I about the screw up the
compressor by doing this?