In article , Leo Lichtman wrote:
You sort of stated your own criterion of when the cylinder should be treated
as empty: there's not enough left in it to get you through the next work
session without worry. You have about 25% of the pressure of a full
cylinder, so you have about 25% of the contents left. At the rate you are
going, with that small torch, you may be able to go for six months or so

directly proportional(?), never thought about it before, but it s/b possible to
calculate the fill "level" from your first pressure reading on the hi side.

it would be approximate, depending on temp and guage accuracy. but what about
the acet.regulators with markings for gas remaining? seems like they could
or you could do the same for other gases. i am surprised i have never seen this
typ of regulator/guage. maybe CO2 fire extinguishers? --Loren