Short fills- how short is too short?

[The Kraken]

Wow a bunch of cocky internet divers... You are Cool.

Honestly, if 200 PSI makes that big of a difference to you, than I apologize, go ahead and whine about it, but if you are diving that close to the edge of your air supply, get doubles.

Would ya pay full price for a case of beer that had one missing???

For many of us, it's more a matter of "give me that for which I am paying".

the K-eg Meister

 

[ClayJar]

I was actually rather flummoxed this weekend by how I managed to have a an AL80 with a 2550 psi fill. It didn't bother me much, as I was using that cylinder for a rinse dive at the springs after a weekend of diving in the Gulf, but it probably would've bothered me much more if I were doing a normal dive.

 

[SparticleBrane]

I'm still amazed that someone would think that warming up their tanks = somehow there's more air inside.

 

[fishb0y]

Why are you amazed? If you only fill your tanks to 2800psi, you can then heat them up for your 3000psi, thus saving wear and tear on your tanks... Geesh, don't you guys ever think out of the box???

 

[SparticleBrane]

Sorry, I forgot the magic tank fairies fill it up while it's being heated.

 

[ClayJar]

Why are you amazed? If you only fill your tanks to 2800psi, you can then heat them up for your 3000psi, thus saving wear and tear on your tanks... Geesh, don't you guys ever think out of the box???

It might be a good idea to include the :rolleyes: smiley so nobody thinks you're serious. Irony tends to get lost in plain text.

For those who may not get the joke, heating up the cylinder doesn't help much when you go to dive it. The water surrounding the cylinder is a very effective heat sink/source, and the cylinder will in very short order approach equilibrium with the surrounding water. This is why you can take a cylinder out of your car and gear up with a great-looking fill only to see it drop considerably during your descent. It's not that the descent is that stressful; the cylinder and the gas inside are merely being rapidly chilled to the temperature of the surrounding water.

Cooling the cylinder while you're filling it means you can pack more gas in for a given pressure (see the ideal gas law, PV=nRT, for the simple reason for this). With the valve closed, nothing you do will add or remove gas, and once you're diving it, the temperature is fixed by the temperature of the surrounding water.

 

[fishb0y]

I considered adding a smiley... but I was too bitter at that time.

 

[SparticleBrane]

I'm just a smart@$$.
(but if you've been around here long enough, you probably already know that)