Info Scuba Cylinder Valve Installation

[Akimbo]

I'll have to dissasemble 40ish cylinders , that vise idea idea with a rachet strap will be a life saver (or a knee saver considering how accurate I am with a hammer).

I really encourage you to use a wrench (improvised or production) instead of a hammer. Talking with XS Scuba, accidently bent valve stems are a common problem. Besides, a wrench is much easier to use and judge proper torque. BTW, you can use a DIN Valve Removal Tool (see above) on a yoke valve by screwing on a DIN-Yoke adapter.

 

[captain]

A large adjustable wrench can be used on valves without flats if the correct procedure is used. I remove and install 1/2" taper thread valves this way with no damage to the valve.
Correct wrench placement, wrench force is away from the O ring glan.

Incorrect wrench placement, the wrench force will crush the edge of the valve into the O ring glan. I have hydro shop damage my valves from incorrect wrench placement. Now I remove the valves before I bring them to the shop.

 

[Akimbo]

Unfortunately, not all valves have any flats that can be used with standard wrenches — like, what the heck were they thinking? Some rebreather and doubles manifold valves can be especially challenging:

 

[Vicko]

I just tap a piece of wood with a hammer on the handle, no damage yet (except to me from missing with the hammer that is )
Not saying it does not happen, just that it never happened to me.

 

[sealark]

All of my tanks aluminum and steel tanks have 3/4 NPS ( National Pipe Straight) with O-rings.

 

[sealark]

I would beat the hell out of the threaded end with a rubber mallet on or off. That end is strong enough to take the beating with a rubber mallet. Once seated good and with pressure on the tank It isn't coming off.

 

[Akimbo]

I would beat the hell out of the threaded end with a rubber mallet on or off.

Clamping two pieces of softwood to it also works, but an extra pair of hands is pretty handy since you are clamping to the "rounds". It wouldn't take me long to make a DIN Removal Tool if I had to change it more than a few times though. I have plenty of DIN plugs and a friend with a TIG welder.

 

[cool_hardware52]

Akimbo, bravo, great info. Loved the history lesson.

For those considering valves for doubles or twins:


Tobin

 

[Akimbo]

For those considering valves for doubles or twins:

Your assembly fixture and technique is the best I have seen, thanks for the info. While we're on the subject of doubles, I have noticed a lot of questions on Scubaboard on how isolation manifolds work. Here are two images that might be helpful:

Image of a cut-away section of the XS Scuba Isolation Manifold.

Schematic diagram of a doubles isolation manifold. Note that the "Post Valves" function as regulator stop valves, not cylinder stop valves.​

 

[bergersau]

Continued from previous post​

DIY Tips
Divers that occasionally service cylinder valves may not be able to justify the cost of tools that aren't on hand. It can be especially challenging when the valve doesn't have wrench flats or requires a large and expensive wrench that you don’t own.

It is not uncommon to use a rubber mallet to tap on the valve to tighten or loosen but that can be difficult on some valves without hitting the plastic handle. The handle can be removed but that increase the risk of hitting the valve stem with the hammer and damaging it. There are better methods.

View attachment 432219
An improvised wrench can be made with some scrap wood, (ideally) a rubber scrap pad, and a clamp. It is especially useful for valves that don't have wrench flats. ​

You can purchase a nicely-made DIN Valve Removal Tool. Another option is to make one with a G5/8" BSP (British Standard Pipe) male plug or a stainless steel DIN plug welded to a piece of pipe or tubing.

A DIN Valve Removal Tool can also work on yoke valves by adding a DIN to Yoke adapter. ​

Holding the cylinder can also be difficult when removing cylinder valves. Here are a few options for an improvised a cylinder vise:

• A wooden fence post and a ratchet/cargo strap
• Cylinder bands for doubles, if you have them
• Use cam bands around the cylinder and a piece of scrap wood. A lever can be attached to the clamped scrap wood

Thanks Akimbo.
Your timing with this thread is perfect - I need to change out my first tank valve this evening. There's nothing very tricky involved but the ratchet strap on the fence post tip is really going to make my life simple.