Argon Bottle setup

[Bob3]

How about a little more science in this discussion?

The amount of heat used to warm the gas will be very small, we'll have to weigh the air & weigh the Argon, and calculate the difference it takes to warm them.
Remember, 1 calorie = the amount of heat used to raise the temperature of 1 gram of water 1 degree.
You're talking just a fraction of a calorie.
There's nothing wrong with Voodo Science (placebo effect).
Heck, deco theory has enough variables that it has a Voodo flavor.
:mean:

 

[roakey]

The issue is not how many calories it takes to warm the Argon, it's how good the argon is at keeping you from warming the water around you (heat transference).

Roak

 

[jessegwalker]

Along the lines of thermal conductivity, argon has a thermal conductivity twenty percent less than air (according to the Avanced Nitrox Diver manual by Lee Somers), and only 1/9th that of helium. When I'm using Trimix as a back gas, I need a separate gas to inflate the drysuit- I pick argon.

 

[zorax]

Here is a nice discussion of argon and other gases that could be used for drysuit inflation and their thermal properties:
http://www.decompression.org/maiken/Why_Argon.htm

What you really want to use is sulfur hexafluoride (SF6)!

 

[mjhlaw]

Looking for some advice on a argon gas tank and reg for diving with a drysuit in cold water. Would appreciate insight on the following issues:
1) size of tank to use and whether steel or aluminum (most guys around here seem to be using steel 13s by faber;
2) recommended first stage regs (reliable in extreme cold, not huge, without huge cost if possible)
3) any additional safety concerns when using this reg (other than not to breath the Argon) Thanks, MJHLAW

 

[oxyhacker]

You may already have one. Just about any reg will do - argon is very dry, and you'll be using it sparingly, so freezeup just isn't a major concern. And you don't really care about maximum flow or IP stability or all the other issues we worry about with breathing regs, for the same reason.

I tend to like cheap, simple unbalanced piston 1sts or the more compact in-line diaphragm 1sts. My current argon reg is a Mk2 SP but it could just as well be any number of others 1sts depending on what I had lying around or could lay my hands on cheap. It almost seems a shame to buy a new reg for argon it's such a perfect application for a good used one.

You should put an OPV (overpressure valve), available from most shops that cater to techdivers and many MO suppliers, on it to bleed off the pressure in the event of HP seat failure to prevent blowing a hose or have runaway suit inflation.

 

[SDAnderson]

My diving is mostly on wrecks, so there isn't a lot of up and down, your results may vary...

I use an AL6 with an old beat up regulator that I've reduced the IP on so that freeflows aren't much of a concern. I went scrounging through the dead puppies bin at the local dive shop and found something that nobody would use as a breathing reg anymore, all I needed to do was have it serviced, tuned for low flow and add a button pressure gauge, an OPV and a lp suit hose. I also use a hose with a wider flange on the quick release so that I can find and break the connection in a heartbeat if there is ever a problem, and of course my knife is located on my waist strap, about 2" away from the hose. For longer/deeper dives, I'll carry a 13 ft bottle to purge my suit with, reserving the 6 for underwater use only. Normally, I'll expect to get about 4 dives from the 6 at recreational depths, more if I purge from the 13. Even on very long, very deep dives in very cold water, the 6 has always been enough gas so long as I use the purge tank on the surface.

Mounting is always an issue, I don't like the pony mount on the backgas - entanglement is a real issue and it's harder to reach should the need arise. I mount mine on my left waist strap, upside down. Most folks do this with a large loop on a couple of screwbands and a bungee retainer on their backplate, I've always felt that this was kind of sloppy and prone to coming loose so I cut the loop and had a couple of velcro patches sewn on, allowing me to secure the tank tightly to my waist. The velcro doesn't last forever, so I had a seamstress make up a dozen or so a couple of years ago - I replace them at the first sign of wear and I'm still working off my stash.

 

[mjhlaw]

Thanks oxyhack. That also seems to be the local advice. I have an old MK 5 I can use if a throw in a new spring (old one cracked in half). Just seems kind of big and clunky and 20+ years on it, but if freezing isn't a concern I guess it'l be fine.

 

[mjhlaw]

Thanks Reef.

 

[DA Aquamaster]

Older Conshelf first stages are ideal. The older ones with only 2-3 LP ports can be had for very little money and parts are still available so they are readily rebuildable. As a bonus, the spring pad adjustment screw on them can be backed off substantially to reduce the IP to a much lower figure.

You should still use an over pressure relief valve in one of the LP ports anyway but the lower IP virtually eliminates freeze concerns and reduces the flow rate in the event things do freeflow.

A low pressure 2015 psi pony is preferable if you transfill your argon without the benefit of a boost pump and I have used a 15 cu ft 2015 psi pony in the past. It offers a lot of volume but is still not overly heavy or too large for the application. It has the advantage of allowing several dives even if a full fill cannot be obtained and that is not always the case with a smaller 3000 psi pony.

That said, I am no longer a true believer in argon and once you don't believe anymore you lose the placebo effect which is about 2/3rds the benefit. Thermal efficiency is only about 1/3 better than air under ideal conditions and I have found a little thicker underwear and/or a bit more air in the suit is more effective than argon and does not involve all the bother and expense.

If you go with the MK V and need a new spring anyway, it may be worth your while to look for a much lighter stainelss steel spring with the correct diameter and working range at the local hardware store. This would allow you to operate the reg at a lower IP and further reduce the freezing concerns. The Mk V would still offer a more than adequate flow rate even at a much reduced IP.