lubricating new tank valves

[wedivebc]

I was taught when installing tank valve (AL80) to apply Corning 111 lubricant to the lower half of the threads and place the o-ring about half way down to let the o-ring find its seat before the valve bottomed out.
The lubricant was to be enough to fill the valleys of the threads.
I have heard others say not to lubricate threads on AL tanks. I recently had an o-ring extrude after installing a new valve and someone at the shop says it happened because I lubricated the threads.
I would like to hear your thoughts on this.

 

[SparticleBrane]

Generally I take a small bit of christolube and put it on the tank threads -- just a tiny bit. Don't want the threads to catch/gall and then screw up the threading or not be able to remove the valve.

What durometer rating was the o-ring? I have heard reports that 70-durometer o-rings for tank necks tend to extrude. 90 is preferred.

 

[skippy31]

I
I have heard others say not to lubricate threads on AL tanks. I recently had an o-ring extrude after installing a new valve and someone at the shop says it happened because I lubricated the threads.
I would like to hear your thoughts on this.

Yes you do want to (lightly) lubricate the threads, but not the o-ring. Make sure the valve is properly tightened, and that your using the correct durometer (90) o-rings.

The method for lubricating the threads outlined in previous post is what I use as well (little dab of lube on button threads of valve).

Mat.

 

[SparticleBrane]

I should also note that I put the o-ring on the valve all the way towards the top where it will sit before I put any lube on. This helps with keeping the lube from getting on the o-ring (just a theory, but it seems to work).

 

[DIVESeekers Jason]

I recently had an o-ring extrude after installing a new valve and someone at the shop says it happened because I lubricated the threads.
I would like to hear your thoughts on this.

Lubricating the threads helps prevent galvanic action which could lead to corrosion. Here is the key:

1) Slide your o-ring on the valve (all the way up and make sure it's not twisted).
2) Put a dab of Tribolube or crysto lube (something O2 compatable if being used with Nitrox) on the base of the threads (opposite end of the o-ring).
3) As you screw in the valve, the lube will naturally work it's way into the threads all the way up until its seated.

O-rings that extrude from the cylinders, typically have way to MUCH lube on them. I do recommend putting a tiny bit of lube on them so they don't dry out.


Hope this helps!

Cheers

 

[JBRES1]

I just took the TDI tank inspection class last weekend, and the training included inspection and assembly.
We were taught to put a little lube on the first 3 threads of the valve so that they (1) help lube the connecting surfaces,ease installation and reduce ware and galling. (2) help prevent galvanic action between dissimilar metals.
Jim Breslin

 

[mrabdiver111]

I just took the TDI tank inspection class last weekend, and the training included inspection and assembly.
We were taught to put a little lube on the first 3 threads of the valve so that they (1) help lube the connecting surfaces,ease installation and reduce ware and galling. (2) help prevent galvanic action between dissimilar metals.
Jim Breslin

When you put it on the first three threads, how much should you put on? Just smear it on liberally or sort of pack it on so that it works it's way to the top? Does this apply to all types of tanks? Im using steel 100hp's.

Rob

 

[NorthWoodsDiver]

you only need a very small amount, if your using the "grease" type lube that is thick like grease dont "pack it" just lightly smear a bit on.

I always see tanks that have copious amount of grease packed into the threads and it makes doing a VIP a PITA cause you have to clean most of it off to see any cracks or signs of damage.

use it sparingly, if your tanks are ever gonna be used for nitrox use an appropriate lube and if some of your tanks see EANx but some dont just use the good stuff on them all. there is little point in even keeping silicone grease around if you dive EANx or O2 to prevent mixups.

 

[mrabdiver111]

I use quite a bit of banked nitrox in both of the 100's, (between 32%-36% mainly). Could you recommend a lube that would be good for those tanks? And should I have the valves taken apart and have them 02 cleaned? I believe they were ready for nitrox right off the bat. I bought them from Scubatoys, online. Is there anything wrong if I didn't put anything on the valves when I bought them?? I put the valves on before I got my Eanx cert. and didn't think about it.

Rob

 

[DA Aquamaster]

I'll confirm that the threads should be lubricated slightly - not much, maybe a bead half the size of a pea.

Either Christolube MCG 111 or MCG 129 or Tribolube 71 or 77 will work fine on tanks used in nitrox or O2 service.

The O-ring most definitely needs to be lubricated. It is extremely important that the o-ring slide into proper alignment with the mating surfaces on the tank and valve. If it si not lubricated this may not happen and the valve may not fully seat. If the valve does not fully seat, you do not have metal to metal contact and that will lead to o-ring extrusion.

It may seem counter intutitve but properly lubricating the o-ring will prevent extrusion not cause it. Proper lubrication means very lightly coating the o-ring so it just has a shine to it. If you can see lube on it, you have too much lube on it.

If there is any potential for the tank to be expsoed to O2 percentages over 40% (ie: use with nitrox mixes over 40% or nitrox fills utilizing partial pressure blending) the tank should be O2 cleaned. Some shops will insist the tank be O2 cleaned anyway for nitrox fills.

If you are going to use nitrox, the o-ring should be Viton rather than nitrile rubber.

The valve should also be O2 cleaned if the tank or valve will be exposed to oxygen percentages over 40%.

As long as the chrome is intact on the valve, dissimilar metal corrosion is a fairly slow process, so a lack of lube will not cause the valve to seize in a reasonable period of time.