Question Valve Question

[Purge]

I'm looking to buy a new pair of cylinder valves and see that some valves seal the bonnet nut with a copper crush washer and others use a #015 o-ring, are there are any pros and cons between the two?

In the past I have seen crush washers that were difficult to remove, but is this the only advantage of one over the other?

 

[Tracy]

Pick one, it really doesn't matter either way. I haven't ever seen either fail in normal use.

 

[SlugLife]

Most modern valves should use an o-ring, unless it's an older tank with a tapered-neck (which uses Teflon tape). I haven't heard of using a crush-washer on scuba-tank valves, so I can't imagine it's very common.

(edit I could be wrong, but I just haven't heard of or seen any with a crush-washer yet)

 

[rjack321]

Most modern valves should use an o-ring, unless it's an older tank with a tapered-neck (which uses Teflon tape). I haven't heard of using a crush-washer on scuba-tank valves, so I can't imagine it's very common.

(edit I could be wrong, but I just haven't heard of or seen any with a crush-washer yet)

Thermos use crush washers (and a few others)

 

[rjack321]

I'm looking to buy a new pair of cylinder valves and see that some valves seal the bonnet nut with a copper crush washer and others use a #015 o-ring, are there are any pros and cons between the two?

In the past I have seen crush washers that were difficult to remove, but is this the only advantage of one over the other?

Oring is easier and cheaper since you can get them by the 50 pack from McMaster. CRush washers are more $$ and harder to source,

 

[SlugLife]

Appears you're correct, I could have done a few minutes of research.

Tips for removing copper crush washer from cylinder valve

The title says it all. I'm overhauling some cylinder valves (Blue Steel FWIW), and the old copper crush washer/gasket is pretty well stuck in there. Any pro tips for getting it out without mucking around too much? It's almost like it's welded in there. Many thanks.

scubaboard.com

 

[Tanks A Lot]

Packing Nuts sealed with an O-Ring are superior.

- O-Rings are much cheaper than copper gaskets.

- By design, water will enter the threads of a packing nut sealed with a copper gasket. Come service time, this will be an additional area that has to get a bit more attention than a comparable valve which used an O-Ring to seal the packing nut. Salts will build up here.

- Copper gaskets are much more prone to cause issues when torqued wrong. Too little and no seal will be achieved. Too much and the gasket will protrude into the far end of seat area where the seat threads sit. A packing nut with O-Ring seal does better in both, low and high torque scenarios. Of course the correct torque is preferable for both...

- Copper gaskets can be a pain to remove if the technician before you torqued it wrong.

Regardless of the above, your choice of valve should not be guided solely by the difference in O-Ring seal or copper gasket. There are a lot more important areas I would look out for.

 

[Johnoly]

... CRush washers are more $$

I don't think this is what you meant by a Crush Washer..........lol !

 

[happy-diver]

You see, in order for attempted humour to come at least close to humour, patience is required
where you should wait for a look I dropped my tank how much do you torque the valve thread

 

[Purge]

Packing Nuts sealed with an O-Ring are superior.

- O-Rings are much cheaper than copper gaskets.

- By design, water will enter the threads of a packing nut sealed with a copper gasket. Come service time, this will be an additional area that has to get a bit more attention than a comparable valve which used an O-Ring to seal the packing nut. Salts will build up here.

- Copper gaskets are much more prone to cause issues when torqued wrong. Too little and no seal will be achieved. Too much and the gasket will protrude into the far end of seat area where the seat threads sit. A packing nut with O-Ring seal does better in both, low and high torque scenarios. Of course the correct torque is preferable for both...

- Copper gaskets can be a pain to remove if the technician before you torqued it wrong.

Regardless of the above, your choice of valve should not be guided solely by the difference in O-Ring seal or copper gasket. There are a lot more important areas I would look out for.

Thanks for the response
Can you be more specific on what the other important areas are that you mentioned?
The valves I'm considering are the following:
- Thermo vs XS Scuba Valve-Difference — XS Scuba - Everything For The Perfect Dive
- Dive Rite or DGX (not sure if these are exactly the same but suspect they are)