PST Tank discussion

[ScubaFeenD]

PST has a long history with hot dipped galvanized cylinder that extends way back into the era of the LP72 and beyond. These are cylinders that just don't die unless really abused. That reputation was carried into the 3500 PSI (DIN only) cylinders and latter the E series 3442 PSI hybrid cylinders that made the HP package available to yoke users. When I started diving in 2005 the E series was the rage with dealers on allocation and divers waiting many months to get cylinders.

Worthington entered the scuba business just as PST was going downhill and the X series is a clone of the PST 3442 PSI product.

The E series 3442 PSI cylinders from PST and Worthington X series are essentially the same products. The buoyancy properties vary slightly between the brands but not enough to effect the decision making process. The specifications vary and as always those specifications are typical and not precise, there could even be some overlap. Not all of the published property charts include the Worthington product but this one from TDL does.

The Worthington galvanize is not as bright as PST but after a few dozen ocean dives you can't tell the difference.

In their prime the PST E series was coming with the Thermo Pro valve. Latter inventory clearance cylinders got a knock-of valve. Same functionality just not as classy.

Worthington is still active in business. PST has been down and out for years now though I hear a gasp once in a while. Both companies had cylinder lines outside of scuba. Worthington is a giant in the cylinder industry.

Pete

Thanks so much for such a concise and on target response!!

 

[rjack321]

So the "LP104 is effectively the same as an HP130" arguments Ive heard might actually be true then?

No. The lp104 is a 2400+ psi cylinder made under the 3AA specification. Its similar but not the same as the exemption series 3442psi hp130 cylinder.

Different steel, different hydro pressures. The only functional similarity is if you can get the "lp" cylinder cave filled to 3600psi. Then its got the same gas volume as a hp130 filled to 3600psi.

3AA specifications will never expire. PST's DOT exemption which allows the 3442psi cylinders to be in service will expire and need to be renewed.

 

[deeper thoughts]

My pst 3442 failed its first hydro and now in the garbage. They say overexpansion might of caused it

 

[rjack321]

My pst 3442 failed its first hydro and now in the garbage. They say overexpansion might of caused it

Was it properly tested with (PST's) prestretch protocol beforehand?

Exemption series tanks (regardless of manufacturer) will frequently fail if this "special" step is omitted.

 

[deeper thoughts]

Was it properly tested with (PST's) prestretch protocol beforehand?

Exemption series tanks (regardless of manufacturer) will frequently fail if this "special" step is omitted.

I have no idea. I dropped it off at Conch republic divers and the person who did the inspection said it failed. My other tank and al80 passed

 

[captain]

This is the procedure, if they didn't follow it it is likely it was the reason for the failure and my feeling is they supply you with a replacement.

 

[Jaeger45]

Any updates to the DOT exemption situation?

 

[Jaeger45]

I hate to respondto my own post, BUT....

Dropped off my doubled E-series PST HP100s (which I love, BTW) for a vis, and an early hydro (due 2012) today. Dive shop called their hydro facility, and they stated that their sources stated that a) hydro, vis, and even fill would be banned after the expiration of the DOT exemption, and b) individuals could not apply for renewal of the DOT exemption, as the libility for any failure would then be "PST and such-and-such applicant". This is in contradiction to info posted elsewhere on Scubaboard.

I have no direct knowledge as to who to believe. It would be really nice if someone with the know-how would apply for the exemption get the ball rolling, if such a thing can happen. Or if someone with DOT would disseminate a final decision.

 

[Ben_ca]

I have 2 PST 100's pass hydro with no issues last June (SF Bay Area)

 

[drbill]

I can only speak to the older line of PST tanks. I had two PST HP120s. Both failed within what I consider to be a relatively short time. The first failed due to significant over expansion during its third hydro. The second failed visual due to serious rust just over a year after its second hydro. I will never buy another PST (of course not!).

This does not specifically relate to the newer PST tanks that were popular just prior to PST shutting its doors. I dive an older steel 72 (1976 first hydro) and a neutral bouyancy Al 80 tank now.