A few fact about acetylene tanks (B-size tanks = 40 cubic feet). The
tank are fill with pith (looks like a very porous plaster) then they
put acetone into the tank.
The acetylene is dissolved into the acetone make it stable. Sort of
like a French dip sandwich. Acetylene is explosive over 15psi, so do
not crack it up trying to get a hotter flame. You only need 5psi for
anything. Including cutting apart a battleship. I have always traded
in tanks and there is only one thing to look out for. That is
condition of the valve stem and regulator seat. Do accept a tank
with a damage regulator seat. The thread should all be there and not
damaged. The valve nut should be tight.
The reason taking a tank home in your car is frowned on is that you
might lay the tank on its side. The acetone will go into the valve
and then into your regulator and eat up any rubber gaskets it come in
contact with. This could get dangerous when the pressure goes over
15psi (pounds per square inch). Regulators can and have exploded as
shown to me by a welding teacher. If you must lay a tank down, when
you get home stand it upright and leave it for a day, till a the
acetone has settled back into the tank.
If you are truly worried about the appearance of your tank (paint
appearance is not a safety issue). Go to the lumber yard and get a
peace of sewer pipe wide enough to hold the tank and tall enough to
cover just the tank but not the stem. Screw it to your bench so the
tank can't knock over. This is safer and will look good. Breaking
off a valve stem is a very bad thing. You never want that to happen.
Sorry to scare you kids to death, but this is a serious business and
these aren't toys. They can and will kill you, if you don't treat
them with respect and know what your doing. I suggest taking a
beginners welding course to learn more about safety. Jewellers have
flown by the seat of the pants for to long now.