Valve Stuck On Al80 Tank

[bhapps24]

I have a 3 year old tank al80 and it is leaking at the cylinder. Last vis was on sep 02. The lds said the valve was stuck and would need replacing do to damge from removing. Does anyone have an idea of what caused this? Would a mgfr warranty this? thanks

 

[rmediver2002]

The valve handle is stuck, the valve is stuck in the cylinder, or the valve was stuck in the cylinder and got damaged on removal?

Jeff

 

[chrpai]

Maybe its just a bad o-ring between the tank and the valve.

BTW is this LDS the same place you had your last VIP done? If the damage is due from removing, then I would think they should owe you a new valve.

 

[bhapps24]

the valve is stuck on the tank and has not been removed yet. And The oring is probably the problem. The LDS suggested it is salt keeping the valve from coming off.

 

[Genesis]

There is no way for salt to get in there.

 

[rmediver2002]

Well nothing wrong with replacing the valve, you should only be looking at around $30 - $35. See what kind of price they will give you on one and then make a decision.

(you could...)

Give this a try though... Make sure all the air has leaked out of the cylinder (open the valve) if the leak was small then it may be holding back some pressure. (hopefully that is not the problem here)

Invert the cylinder and soak it in a solution of 50%water / 50% white vinegar.

Let if soak for about 20 minutes and then lightly tap it with a rubber hammer... Your going to have to hit the valve handle to get leverage usually so be as gentle as you can and make sure you turn the valve all the way in first to try and protect the stem.

If it does not come out then soak again for 20 minutes and tap (a little harder) if it still does not come out you might want to consider really nailing it with the hammer or taking a big wrench to it... At this point go ahead and take your frustration out!! But realize you are going to have to spend a few bucks on a valve after you get the old one out.

Good luck with it, hopefully it works for you!!

Jeff Lane

 

[FredT]

Aluminum tank valve threads need some lubricant to keep them free if they are used in salt water. Normal thread lube is silicone or O2 safe cristolube. Better for non-O2 tanks is Never-Seez Blue Molly from Bostik or a molydisulphide dry spray lube. Both the latter are a bear to get off if you ever intend to O2 clean the tank or valve

If the shop hasn't screwed the pooch yet try heating the valve and tank assembly in boiling water. Then clamp down the tank while torquing the valve with a cold wrench . Thermal expansion may loosen the valve enough to get it to come out. This trick takes a good tank vise and a large boiling pot.

OTOH if it's leaking from the tank threads you may have a dead tank from neck cracking anyway.

FT

 

[The Chairman]

then they have already tried the "rubber mallet to the valve handle" trick and have ruined your valve. It is probably NOT really stuck. Use a LARGE adjustable Wrench (18" or better) and any hammer on the wrench. My bet is that by the third whack you will have it off.

NOW... if that gets the valve off, then you should expect the shop to pay for your new valve. Valves should NEVER be loosened or tightened by blows to their knob. It doesn't take much impact to ruin a perfect valve this way. Yes, I used to do it that way too... until I ruined a perfectly good valve just by popping the knob with the palm of my hand (not even a hammer). Let them learn from their mistake (if that is the case) and not have it cost you needlessly.

 

[pescador775]

Bhapps, how about letting us know what you did and what was found. Chrome plated brass valves don't normally seize in the tank neck since they are removed so often during routine inspections. Long ago, I saw some Navy aluminum tanks with that problem but they had beryllium copper valves which had been in place for years.

When replacing the valve, a bit of silicone, Christolube or Krytox on the threads would be a reasonable precaution. I wouldn't use anything else due to odor or toxicity. Silicone shouldn't be used if the tank is to be charged with oxygen (as in partial pressure mixing).

Most valves have a machined flat for wrenching. The tank should be secured in a chain vise. Use newspaper to protect the metal from gouging.

 

[scubasean]

NetDoc once bubbled...
Valves should NEVER be loosened or tightened by blows to their knob. It doesn't take much impact to ruin a perfect valve this way. Yes, I used to do it that way too... until I ruined a perfectly good valve just by popping the knob with the palm of my hand (not even a hammer). Let them learn from their mistake (if that is the case) and not have it cost you needlessly.

How should they be removed? My LDS uses a rubber mallet on the knob...

--Sean