PST Tanks...Still Worth Buying???

[redacted]

it's not pedantic, it's federal law and DOT requirements, as well as distinguishing between two very different style of tanks.

3500psi tanks aren't legally allowed to have yoke valves on them, so they have different necks on them to make sure it doesn't happen. The importance of it is when buying used tanks because a "HP120" and a E7-120, while physically almost identical, are actually VERY different bottles. The 100's from PST are more similar in buoyancy characteristics, but it becomes even more important to distinguish when you add in the Worthington E7-100's which are quite different than the PST 100's either the E7 or the true HP tanks.
Now, this is only crucial when discussing the 80's, 100's, and 120's at 7.25" diameter, because PST never made the E8 series in HP tanks, but it is important to distinguish between the two properly, especially when discussing Worthington vs. PST vs. Faber's E-series bottles because far too often the "I have HP130's" comes up, but the PST130's are VERY VERY different than the Worthington 130's, sharing only a diameter and nominal tank capacity in common. All other specs are very different, height, weight, actual volume, buoyancy characteristics.

Don't you just hate it when the rest of the world is wrong.

https://www.divegearexpress.com/gas/faberhp.shtml

XS Scuba Worthington Steel Cylinder Specifications

Asahi HP 100 cu ft Steel Scuba Diving Tank Air Cylinder - Scuba Tanks : House of Scuba

Amazon.com : 80 Cf Scuba Dive Tank Faber Blue Steel Hp 3442psi New : Scuba Diving Oxygen Tanks : Sports & Outdoors

 

[tbone1004]

you can do that when you are talking about companies that never made true high pressure tanks, faber never made a 3500psi US tank to my knowledge, neither did Worthington. Asahi and PST did, and since the tanks in that line are similar, it is important to distinguish between what the old HP tanks were, and the newer E series or X series were when you are discussing them. Same as it is important to note whether the Faber tanks being discussed are the old ones that OMS imported and were made of the old alloy, or the new ones. Same name, very different tank characteristics.

 

[redacted]

you can do that when you are talking about companies that never made true high pressure tanks, faber never made a 3500psi US tank to my knowledge, neither did Worthington. Asahi and PST did, and since the tanks in that line are similar, it is important to distinguish between what the old HP tanks were, and the newer E series or X series were when you are discussing them. Same as it is important to note whether the Faber tanks being discussed are the old ones that OMS imported and were made of the old alloy, or the new ones. Same name, very different tank characteristics.

It seems to me that you are the only one making that distinction. Others seem to be happy calling all tanks rated for more than 3000psi Hp pressure tanks. Most also recognize that older HP tanks in the USA will probably require 300 bar din valves.

 

[victorzamora]

It seems to me that you are the only one making that distinction. Others seem to be happy calling all tanks rated for more than 3000psi Hp pressure tanks. Most also recognize that older HP tanks in the USA will probably require 300 bar din valves.

While I call the 3442psi tanks "HPs" like most....tbone is FAR from the only one making that distinction in these forums.

 

[redacted]

While I call the 3442psi tanks "HPs" like most....tbone is FAR from the only one making that distinction in these forums.

What value do folks see in such a distinction and what label are they trying to assign to tanks that are .GT. 3000 and .LT. 3500?

 

[tbone1004]

It isn't a 3500 vs a 3442 psi quip, if they had taken the same tanks that were rated at 3500psi, put a 3/4" neck on them, and rated them for 3442 then it would be a very different discussion, the problem is they didn't do that and went all out and redesigned the tanks from the alloy on up. Only things that stayed the same were the diameter and the nominal volumes. None of Worthingtons tanks actually hold the CF that their name implies. If I go out and say that HP100's are the best overall tanks ever made, which in my opinion they are, I am directly referring to the PST HP100's rated at 3500 psi. My opinion of the E7-100's from PST is the same, though they are very difficult to find because they were only made for such a short amount of time. My opinion of the X7-100's from Worthington is very different because they are shorter, heavier, and more negatively buoyant. My opinion of the Faber F7-HP100's is similar to the PST's, but I prefer hot dip to spray galvanized coatings, and it is 1lb less negative than the PST's, so again very different tank

You mentioned that people are happy qualifying any tank over 3000psi HP, but that also includes the medium pressure tanks that Faber made with service pressures of 3180, and PST made with service pressures of 3300. That MP-100 from Faber is a brick at 7.25lbs negative when empty, great if you're diving a thick wetsuit in a stab jacket in the middle of the North Atlantic, but a far cry from their "HP100" that is -0.6lbs when empty.

 

[redacted]

It isn't a 3500 vs a 3442 psi quip, if they had taken the same tanks that were rated at 3500psi, put a 3/4" neck on them, and rated them for 3442 then it would be a very different discussion, the problem is they didn't do that and went all out and redesigned the tanks from the alloy on up. Only things that stayed the same were the diameter and the nominal volumes. None of Worthingtons tanks actually hold the CF that their name implies. If I go out and say that HP100's are the best overall tanks ever made, which in my opinion they are, I am directly referring to the PST HP100's rated at 3500 psi. My opinion of the E7-100's from PST is the same, though they are very difficult to find because they were only made for such a short amount of time. My opinion of the X7-100's from Worthington is very different because they are shorter, heavier, and more negatively buoyant. My opinion of the Faber F7-HP100's is similar to the PST's, but I prefer hot dip to spray galvanized coatings, and it is 1lb less negative than the PST's, so again very different tank

You mentioned that people are happy qualifying any tank over 3000psi HP, but that also includes the medium pressure tanks that Faber made with service pressures of 3180, and PST made with service pressures of 3300. That MP-100 from Faber is a brick at 7.25lbs negative when empty, great if you're diving a thick wetsuit in a stab jacket in the middle of the North Atlantic, but a far cry from their "HP100" that is -0.6lbs when empty.

Sure, anytime you really want to get specific, you probably need to be talking Manufacturer, nominal capacity and pressure rating. But I see little value in trying to create a line between 3500 HP and 3442 HP by only calling one HP. BTW, aren't the 3180 psi rated tanks capable of 10% overfill making them 3498? Talk about a thin line on pressure rating. But weight and buoyancy are another matter.

 

[victorzamora]

Sure, anytime you really want to get specific, you probably need to be talking Manufacturer, nominal capacity and pressure rating. But I see little value in trying to create a line between 3500 HP and 3442 HP by only calling one HP. BTW, aren't the 3180 psi rated tanks capable of 10% overfill making them 3498? Talk about a thin line on pressure rating. But weight and buoyancy are another matter.

The main difference is actually the thread size for the valves. 3442psi still gets the standard 3/4" valve. The true HPs get the 7/8" "skinny" thread valves only and are DIN only. True HP tanks are also no newer than a certain age as they stopped being sold after a certain point due to the 3442 popularity.

 

[Michael Guerrero]

I just looked at the tank necks. They are X8 130s (i.e., Worthington) .

How do I close a thread?...

 

[a878bob]

I have been keeping an eye out for the PST renewal, nothing yet, as it expires at the end of the month.

??????

I just had mine hydroed early, just in case.