pony bottle question

[TMHeimer]

Question for pony bottle users. I've made use of mine once. Ideally you never use it. How often do you get it visualed and re-filled? Hydros are done to check on metal fatigue, which is generally cause by repeated filling and emptying of a tank. So how often would you have to get it hydroed if it was almost never used and there wasn't a 5 year (US/Can.) rule?

 

[Scuba_Noob]

I always carry my pony on solos, but I've only used it to practice drills. I refill it every few months, just because I don't want to let the air sit around (though it should still be good). I vis and hydro it at the normal times. If there were no rules, I'd still do the hydro and vis whenever I get my regular tanks done, just to be safe. It doesn't cost much, and I'm a conservative person.

 

[SeaCobra]

So, there isn't any fatigue caused by just holding the pressure?

 

[Kronek]

So, there isn't any fatigue caused by just holding the pressure?

There is, but its not the same type of fatigue. While any metal fatigue is bad, holding pressure keeps it at the same level of fatigue. Where as filling it allows it to contract, expand, and do all kinds of weird stuff.

 

[AfterDark]

There is, but its not the same type of fatigue. While any metal fatigue is bad, holding pressure keeps it at the same level of fatigue. Where as filling it allows it to contract, expand, and do all kinds of weird stuff.

Kinda like bending a paper clip over and over. My pony has VIP a sticker and a hydro stamp, no LDS that I know will fill it without those so when they expire I take care of it.

 

[lowviz]

As Scuba_Noob and AfterDark said, take care of biz.

My pony gets topped off fairly frequently. I charge the line then turn off the valve before each dive and use the pony when washing my reg sets. -get a transfill whip.

 

[DandyDon]

I drain mine completely before a trip and before coming home so I can fly with it, so I never thought about trying to avoid the rules. I do have a 80 cf tank that sit in my closet full for years as I just never used it so I didn't viz it annually nor hydro it until it was time to hydro the pony, and if I don't find a buyer it may sit there for years full again - but if you are using the pony for dives, don't you ever have to refill it?

If you can carry it on dives for 2 years still full, I guess that's fine - but I'd have it vized before I refilled it even if I owned a compressor.

 

[g1138]

So, there isn't any fatigue caused by just holding the pressure?

There is, but its not the same type of fatigue. While any metal fatigue is bad, holding pressure keeps it at the same level of fatigue. Where as filling it allows it to contract, expand, and do all kinds of weird stuff.

I think that was a rhetorical question directed towards the OP.

 

[Edward3c]

Question for pony bottle users. I've made use of mine once. Ideally you never use it. How often do you get it visualed and re-filled? Hydros are done to check on metal fatigue, which is generally cause by repeated filling and emptying of a tank. So how often would you have to get it hydroed if it was almost never used and there wasn't a 5 year (US/Can.) rule?

So far in 7 years I've only used mine for practice/training.

I top it via a whip I bought when I first got the pony.

That said I still follow our local guidance: visual 2 1/2 years full hydro 5 years.

Kind regards

 

[James R]

My pony bottle is also a bottle i use for deco (AL40), so it gets used a lot, and refilled fairly often with whatever mix that I need. It gets a fresh O2 clean & viz yearly.