In article , Don Bruder says...

... Acetylene
"boiling" out of solution to replace what you've tapped out of the
cylinder is exactly the same mechanism in operation, just working on
different materials.

Not *exactly* boiling, which is phase change from liq. to gas, but
rather it's the acetlyene coming out of solution, more like CO2
when you open up a soda bottle. The acetone's not supposed to
boil, and of course if the soda bottle is shaken up before
opening the acetone can bubble out into the regulator, not
good.


Additionally, acetylene cylinder are *NOT* hollow cylinders, the way
oxygen and other cylinders are - If you were to break one open somehow
(HIGHLY not recommended outside of properly equipped facilities - unless
you *WANT* to die) you'd find that it's almost entirely filled with a
highly porous block of something that looks much like concrete. This
"rock sponge" is what soaks up the acetone that the acetylene dissolves
in, preventing you from getting spits and spurts of raw liquid acetone
coming out the end of your torch. Gaps and voids in it are a certifiable
Very Bad Thing(TM), which is one of the (if not the main) reasons that
dropping an acetylene tank any distance is a Bad Thing(TM) and grounds
for having that tank pulled from service and stored someplace
"bomb-proof" until it's been inspected and tested to be sure the
"stuffing" is still intact and working as intended. If you ever get
handed a cylinder that "rattles when rocked" (something *INSIDE* the
cylinder rattling, not "stuff attached to the cylinder") immediately
hand it back - *GENTLY* - and demand another one. The "rattler" almost
certainly has damaged media in it, and is unsafe. It's unlikely, due to
the pre-fill inspection, that you'll ever get one, but "unlikely" and
"impossible" aren't equal.

They used to use asbestos fiber for the filler, somebody told me
that for a while it was diatomaceous earth.

There's a lot of half-truths and nonsense circulated about acetylene
because most folks don't understand how the molecules behave.
Clearly the ullage space above the filler is not full of liquid,
though it has acetone vapor in it. But the front end of the regulator
probably isn't saturated with that, so why doesn't the 200 psi
gas there decompose? The answer is that the mean free path length
is too short.

Another source of excitement is when you suggest that folks shouldn't
use pure copper tubing to manifold acetlyene cylinders.

"But my regulator's made of BRASS and brass has COPPER in it, right?"

Jim


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