Tank leak...this can't be good

[blackvans1234]

A note- I watched the guy at the shop tighten the valve and then hit it with the mallet so it was tight.


Anyway, onto the verdict!
I went to the LDS, and they drained the last 100psi out of the tank, and upon unscrewing the valve, we saw the problem, salt buildup between the lip of the tank and the valve (exteriorly)

Guess ill start rinsing the tank more thoroughly. It was coated with salt :-\

Drain tank, take the valve off, check the thread and o-ring are clean, check its the correct o-ring and replace the valve. Its not that uncommon for neck o-rings to leak especially in new tanks.
Simple to do at home.

read the first quot

 

[String]

If its sealed properly there is no way for salt to get in there to build up in the first place. It can only form on the external/non-sealed side.

If salt build up is causing a leakage its the result of an incorrect o-ring or fitting of the valve in the first place.

 

[Buoyant1]

If the cylinder was filled too fast, and the o-ring wasn't seated properly...it's possible that the o-ring melted a tad and extruded ...or the o-ring is bad, or it wasn't seated correctly...take it back, tell them the problem, and I'm sure they'll replace, re-seat, and re-fill!

 

[captain]

If its sealed properly there is no way for salt to get in there to build up in the first place. It can only form on the external/non-sealed side.

If salt build up is causing a leakage its the result of an incorrect o-ring or fitting of the valve in the first place.

Exactly, there is no way salt build up will cause a properly installed valve and o ring to leak, someone screwed up installing the valve.

 

[blackvans1234]

It was on the external side, either way, he replaced the o-ring.
Time will tell

 

[davetowz]

Good to hear a happy report about working with your LDS!

 

[Max Speed]

Yeah, maybe someday they'll be able to buy a wrench to supplement the hammer.

 

[AfterDark]

Rubber mallets have been used on tank valves long before you even thought about diving. Hand tight, a couple solid raps and your done.

 

[String]

Rubber mallet is all you want for a tank. You certainly don't want a spanner and risk overtightening. Looks here like the LDS screwed up fitting the valve in the first place and has now fixed it. It happens. Salt is not to blame though - thats a weak excuse.

 

[SDAnderson]

If the cylinder was filled too fast, and the o-ring wasn't seated properly...it's possible that the o-ring melted a tad and extruded ...or the o-ring is bad, or it wasn't seated correctly...take it back, tell them the problem, and I'm sure they'll replace, re-seat, and re-fill!

Hot filling was not the cause of this problem. The o-rings don't melt, though they can burn, especially in high-oxygen/high-pressure environments. Maximum service temperatures: Buna-N = 200°F (94°C); EPDM = 250°F (121°C); Viton = 300°F (149°C). We're talking hot enough to boil water and nobody has fills that hot.

Rubber mallets have been used on tank valves long before you even thought about diving. Hand tight, a couple solid raps and your done.

Rubber mallet is all you want for a tank. You certainly don't want a spanner and risk overtightening. Looks here like the LDS screwed up fitting the valve in the first place and has now fixed it. It happens. Salt is not to blame though - thats a weak excuse.

Drain tank, take the valve off, check the thread and o-ring are clean, check its the correct o-ring and replace the valve. Its not that uncommon for neck o-rings to leak especially in new tanks.
Simple to do at home.

Cause, meet effect. Though a relatively standard practice in dive shops, the fact that rubber mallets have been used since pre-history is the reason its not uncommon for neck o-rings to leak. In experienced hands, the rubber mallet can be effective at tightening the valve however the ongoing problem with leaking seats is proof that the hands aren't as experienced as they think they are. Even in experienced hands, the rubber mallet is hard on valves: bent stems and distorted bonnet nuts just being two of the most common pieces mauled by the force of the mallet. A cylinder clamp and a torque wrench with a crows foot is a better idea. Of course, that costs time and money and requires some semi-fancy math but still...