In article ,
jim rozen wrote:

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.

Right. Maybe a poor example. But the mechanism is the same: A drop in
pressure. Depressurizing water at an arbitrarily selected temperature to
below the vapor pressure of steam at that temperature makes it boil into
steam (albeit cold steam) while depressurizing acetylene-saturated
acetone to a point below the vapor pressure of acetylene allows it to
come out of solution, leaving the even-lower vapor pressure acetone in
liquid state.

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.

Absolutely correct. That's also the prime reason you don't use an
acetylene cylinder that's been laying on its side for more than a few
minutes without first standing it up and letting it "settle" for an hour
or so - Liquid acetone (with dissolved acetylene) may still be pooled at
the valve if you hook up too soon. Most definitely a "not good" thing.

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

I've also heard of compressed burlap *WAY* back in the long ago, packed
fiberglass, glass beads like in the resin-columns of water softeners,
and a whole slew of other porous, tightly packable materials.
Pumice-stone is the one I was first introduced to and am most familiar
with.

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