Tank / Gauge Failure

[CanMike]

Just had this happen.. Crazy.. Lucky I was just pressure testing and was only at 200 BAR and not higher.

Anyone have this happen? Looks like tank is okay and valave is okay.. Just the O-ring blew out. I had it on tight.

Mike

 

[grackleblast]

You didn't have the valve tightened up enough. The pressures these tanks hold , just the slightest small void will blow the o-ring at the neck. I use 90 durometer o-rings when replacing the valve , and finish tightening the connection with a rubber mallet. What size tank is that ? I have extra 0-rings for the larger tanks with the 7/8 -14 unf valve. If so, pm me and I'll send you a couple.

 

[DesertSilver]

When I did an inspection of the inside of my scba tank I just hand tightened the valve and had no problem.

 

[CanMike]

YA thats what I thought as well.. From my Scuba diving its just hand tightened snug.. I guess these require a little bit more encouragement.

I should have a spare o-ring that was included.. It held for 48 hours and then let go this morning. WE heard a rustling in the garage as the tank started moving around a but.

Thanks for the offer on the o-ring.. I'll hit you up if I need. Its a 4.7L Carbon Tank.

Mike

 

[IKnowNutin]

Was that a replacement o-ring or ..............? I haven't had to crank down on any of my valves for a non-leaking seal either......yet. That's with brand new o-rings correctly sized. Just hand snugged with a dab of silicone grease on the o-ring's mating surfaces. I did have a bottle gauge seal let go, though. Wife and cats didn't respond well to that

 

[CanMike]

That was new out of box with o-ring pre installed and snugged down by hand.

Mike

 

[Dead-On]

My gauge crapped the bed and I'm waiting for a replacement.

 

[Mike_Lenardon]

You're only suppose on hand tighten the valves on carbon fiber tanks

 

[IKnowNutin]

I have to take back what I said earlier about a leaky gauge seal. I assumed it was the gauge because I had just reinstalled it before the leak occurred. Wrong! The valve to tank O-ring let go right behind the gauge just like the OP's. Are these a common size in mm? My calipers say 18mm ID x 3mm CS on the blown out ring and valve stem. No spares on hand ....

 

[jarmstrong]

what brand of tanks and valves are these problem children, that can't keep an o-ring in it's groove?

 

[CanMike]

Mine is a Tuxing. China.

I changed o ring and tightened a bit more. Still hand tight but very hand tight now. Will see how it goes.

Will take it to 2500 PSI and leave for a couple days.

 

[IKnowNutin]

Mine is a Tuxing 2L bottle with a cheap Palm Beach Air valve.

I found an O-ring in my Leshiy 2 reseal kit that fit the valve stem and bottle groove closely. Snugged the valve up firmly by hand and pumped it up to 300b last night. It's held pressure so far .......

 

[Humdinger]

Bulging o-rings indicate one of three possible issues.
The o-ring is undersized for the application.
The valve hasn't been tightened down enough.
The durometer of the o-ring is too soft for extreme high pressure use. Most high pressure o-rings are Buna 70 or Buna 90.