Valve to cylinder torque

[JackD342]

Pretty sure if the video was different for Steel Alec would have included that information.

I’m no expert so will let someone else say definitively.

Note that valve companies Sherwood and Thermo at least do not differentiate torque specs based on type of cylinder, so I would also say that in the absence of a specific manufacturer recommendation they would be the same. And Luxfer guidance specifically defers to the valve manufacturer if available, so that sounds to be your best starting point.

 

[BRT]

For US based specs, so far you have Luxfer saying 50 ft-lbs (+/-10), and Sherwood saying 40-50 ft-lbs. I'll add that Thermo valves say 50-75 ft-lbs. Which all combined is why I re-install at 50 ft-lbs when working on cylinders and don't sweat what brand it is. (My recollection is that 40-50 was also mentioned at some point in a PSI-PCI course in the past, but I might be mistaken.)

Or a good tap with the heel of the hand.

 

[abnfrog]

hand bump both steel and alum.......unless its a half inch tape them it gets way more complicated ..used lots of wrenches to take apart tanks put together wrong , but never use one for assembly (unless taped )

 

[2airishuman]

For 1" NPSM and 7/8 UNF thread forms with an O-ring, the torque doesn't matter very much, which is one of the benefits of this system. I believe that it is important to tighten the valve until it is seated, at which point it won't turn much more even if a great deal of torque is applied.

The tapered (NPT/NGT) threads require much more torque, and a cylinder vise is usually required. Just how much depends on the kind of thread dope you use, teflon requires less. I've been using oxygen-grade teflon tape dope for the last few years as it seals well and fits with my strategy of avoiding any materials that are not oxygen compatible even though I dive air. The torque specs upthread may be intended for these threads.

 

[abnfrog]

I ALWAYS use only o2 grade Teflon tape that's all I buy , that way im sure