How easy to remove/replace pony valves when traveling?

[flots am]

From the below "use the least possible torque to make a leak-tight seal". Clearly least possible could be hand tight, correct?

Maximum is not a starting point.

TABLE 1
Maximum torque for North American new, straight-thread brass valves installed into new Luxfer aluminum alloy cylinders and composite cylinder liners—use the least possible torque to make a leak-tight seal

People seem to be missing the o-ring part. Minimum could easily be hand tight.

If the valve is screwed all the way in, even just finger tight, and the o-ring is leaking, it needs to be disassembled, checked and cleaned/repaired/condemned.

A wrench isn't going to fix it.

 

[PeterNBiddle]

NONONONONo. This is a CGA document. Damn it guys pay attention. SCUBA valves are ORB connections using viton or similar o-rings like the hoses on your 1st stage. These valves are not like NPT or PTFE ringed valves on CGA tanks.

If you have tank certs you ought to know this already or you did a scuba only cert class (which is ok, but don't extrapolate from wrong data).

Lets be clear - you may know the tank mfg name because of SCUBA, but tank mfgs make tanks for everything imaginable that can be compressed and put in them. SCUBA and SCBA are a small subset of all the tanks made. And they are unique in their design and application. Don't confuse with them with rest of the worlds compressed and liquid gas containers.

Let me read that document for you. Because you clearly didn't read it yourself.

Here's the first couple of SENTENCES.

"The goal of the installation process is to install a valve with the least amount of torque or tightness that will make a leak-tight seal that lasts throughout the use of the valve-cylinder assembly. This Luxfer Technical Bulletin give torques that should not be exceeded during installation of straight-thread valves of US thread designs and provides information about O-rings and leak-tight seals."

Orings, orings, orings, all over the place! Not tapered, no Teflon. ORINGS. It's like a tire-dump of orings.

BTW this doc is straight off their scuba support page. Feel free to explain to them that it's just all wrong for scuba tanks.

 

[OtherHalf]

Thanks for the data Peter. Several years ago manufactureres recommended 75 foot-pounds, then several manufactureres reduced the recommended torque to 50 foot-pounds.

Looks like the data that Peter quoted was effective as of Sunday, 20 March 2011, maximum torque is anywhere from 50 to 100 ft-lbs depending on the valve.

Gracias.

And yet maximum torque listed from catalina is 50, and recommended is 40. Going to max torque is 25% higher than recommended.

They state right on their page:

"Hand tightening of the valve should seat the valve completely on the cylinder (i.e. no gap between the valve and the cylinder). If there is still a gap between the valve and the bottom of the cylinder lightly tap the valve handle with a rawhide or rubber mallet to seat the valve completely. The valve should only rotate 45^o (1/8 of a turn) from the point of hand tightening to fully seated. If you decide to seat the valve using a torque wrench, following are recommended torque values by Catalina Cylinders and the CGA: "

Luxfer's page lists higher torque values for new cylinders into new tanks without lube, but repeatedly states:

"Use minimum torque values to make a leak-tight seal that will last throughout the use of the assembly. "

I can torque my cylinders to hand tight and not have a leak. (I do use an O2 safe lube on my vavles and a new o-ring with every install), seems reasonable you could do the same, have a leak free fitting, and be totally safe. Why always approach the maximum?

 

[Doc Harry]

...tap the valve handle with a rubber mallet to seat the valve completely...

 

[teknitroxdiver]

My time working on mechanical things has taught me that if there's something to be tightened, some people can't help but tighten it as tight as possible despite relevant torque standards.

 

[Doc Harry]

There is a saying: "If the minimum wasn't good enough, then it wouldn't be the minimum."

The same applies to the maximum. If the maximum wasn't acceptible, then it wouldn't be the maximum.

 

[drrich2]

Since this thread might serve as a reference for someone else, and Spare Air was mentioned by me at the out set, here's a link to their page on it, and here's what I want to share from that:

How to Fly with Spare Air​

​

​

When carrying SPARE AIR on a commercial aircraft, the system must be empty and according to TSA regulations, the regulator must be unscrewed from the cylinder so they can be sure that it is empty.

1. 
   [*=left]To empty all the air out of the SPARE AIR press the Purge Button until no more air is released. Unscrew the regulator from the cylinder counter-clockwise (no special tools are needed – it is screwed on hand tight).
   [*=left]If the regulator does not unscrew easily DO NOT force it or use tools, instead soak the entire SPARE AIR in a 1-1 vinegar & water solution overnight to loosen any salt corrosion. Leave o-ring, washer and exhaust discs on the regulator.
   [*=left]Place the regulator and cylinder in a Ziploc plastic bag to protect and keep them clean. (Option - purchase the "SPARE AIR Travel Pack" which includes its own carrying bag - see below.) Keep SPARE AIR regulator and cylinder threads clean and dry. Include SPARE AIR Owners Manual so TSA employees can refer to it if they have questions.
   [*=left]Pack SPARE AIR in your checked or carry-on baggage.
   [*=left]Reattach the regulator and cylinder and refill SPARE AIR when you reach your dive destination. You may lightly lubricate the tank o-ring with a small amount of silicone spray or grease - NEVER use a hydrocarbon based oil. DO NOT force regulator onto tank - if you feel resistance stop and unscrew and start again.
   [*=left]Replace tank o-ring after product has been disassembled and reassembled 3 times, or o-ring shows signs of wear or air leakage. Tank O-ring size is 016 and you should be able to purchase from any dive shop.

So, with Spare Air, hand tight is supposed to be okay.

Richard.

 

[matt_w]

You mis-read my statements, take another look.



50 ft-lbs is only the manufacturer's specifications. Everyone is free to ignore the manufacturer's recommendations for cylinders that they own, control, and manage.

luxfer says 50 is the maximum and quite clearly says: "Maximum torque for North American new, straight-thread brass valves installed into new Luxfer aluminum alloy cylinders and composite cylinder liners—use the least possible torque to make a leak-tight seal"

So if hand tight makes a leak tight seal, it is the manufacturers specification, in fact it may exceed their recommendation. Most of their document on valve torque is about the damage that can be caused by too much torque.





Sent from my iPhone using Tapatalk

 

[maniago]

Let me read that document for you. Because you clearly didn't read it yourself.

Here's the first couple of SENTENCES.

"The goal of the installation process is to install a valve with the least amount of torque or tightness that will make a leak-tight seal that lasts throughout the use of the valve-cylinder assembly. This Luxfer Technical Bulletin give torques that should not be exceeded during installation of straight-thread valves of US thread designs and provides information about O-rings and leak-tight seals."

Orings, orings, orings, all over the place! Not tapered, no Teflon. ORINGS. It's like a tire-dump of orings.

BTW this doc is straight off their scuba support page. Feel free to explain to them that it's just all wrong for scuba tanks.

Wait a cotton picking minute Biddle. I AGREE WITH YOU. I didn't agree with your torque settings quote. But we totally agree, hand tight, maybe a "rubber" mallet tap. That's all that's needed with ORB fittings. Somehow what I said - which you will note has always been wrt ORB fittings - got assbackworded. Not sure how it did, but I'll take the hit for that - mia copa.

Now, wrt to the Doc - Doc, you got CGA data for non-ORB valves....

 

[PeterNBiddle]

Wait a cotton picking minute Biddle. I AGREE WITH YOU.

You're not the first person to say that... No doubt also not the last. : D