Steel HP 100 Tanks Question

[Clark Fletcher]

Until the other day, I had two Genesis HP 100 Steel tanks (3442 PSIG). If my research is correct, these are Sherwood tanks made in Japan. They are clearly stamped with "Japan".

Two days ago, I had the opportunity to purchase two more HP 100 Steel tanks for a reasonable price (which I did). By the markings on the tanks, they are Worthington tanks and are clearly marked as HP 100 tanks (3442 PSIG).

While the two different tanks are exactly the same height, the two Worthington tanks are noticeably larger in outside diameter. So much so that it's noticeable without even measuring or even without the two different manufacture tanks sitting side-by-side.

Not that it really matters in the big scheme of things but, I'm guessing that the Worthington tanks have a much thicker cylinder wall thickness than the Genesis tanks. Again, doesn't really matter but, I'm curious. Can anyone confirm this to be the case?

 

[2airishuman]

The HP cylinders from Japan I'm aware of are all spun cylinders made by Asahi. They are clearly stamped "spun" and would have exemption/special permit 12079 (DOT-E-12079 or DOT-SP-12079) stamped before the service pressure.

The cylinders would have similar wall thickness. The Asahi cylinders, being spun, have a thicker bottom and are therefore heavier and more negatively buoyant for a given size compared to Worthington and PST cylinders.

I would suggest measuring the diameter of the cylinders to see what you have. HP-100s are 7.25" in diameter. The worthington cylinders would be marked X7-100 if they are that size. If the Asahi cylinders are smaller than 7.25", they are probably not HP-100s.

 

[guruboy]

Genesis Japanese HP100 tanks should be 3500psi, no?

 

[runsongas]

not all of them. the older ones were 7/8 neck and 3500 psi, but then they switched to 3/4 neck and 3442 psi. same as the pst hp100 and e7-100 being nearly identical except the e7-100 has a modern 3/4 neck.

 

[outofofficebrb]

If they are the X7-100s, they are great tanks and are hard to find now. They have excellent buoyancy characteristics when empty...IIRC -2.5 lbs?

I have 2 and love them. I couldn't find a 3rd and 4th so ended up getting Mr OOO the new Faber 100s instead.

 

[Eric Sedletzky]

If they are the X7-100s, they are great tanks and are hard to find now. They have excellent buoyancy characteristics when empty...IIRC -2.5 lbs?

I have 2 and love them. I couldn't find a 3rd and 4th so ended up getting Mr OOO the new Faber 100s instead.

Wait a minute, X7 100's are hard to find now???
I haven't looked at tanks to buy in many years now, but the last time I looked the 3442 line was the latest best go-to tank. What happened?

 

[Tug]

Wait a minute, X7 100's are hard to find now???
I haven't looked at tanks to buy in many years now, but the last time I looked the 3442 line was the latest best go-to tank. What happened?

Worthington has stopped producing SCUBA cylinders and while Faber has started producing hot dipped galvanized cylinders recently, for a few years the only steel cylinders were the triple dipped Fabers and the spun Asahi tanks.

 

[outofofficebrb]

Wait a minute, X7 100's are hard to find now???
I haven't looked at tanks to buy in many years now, but the last time I looked the 3442 line was the latest best go-to tank. What happened?

Sorry to be the bearer of bad news! They don't make them anymore.

Worthington has stopped producing SCUBA cylinders and while Faber has started producing hot dipped galvanized cylinders recently, for a few years the only steel cylinders were the triple dipped Fabers and the spun Asahi tanks.

This! While Faber makes HP100s, they are not the same dimensions (taller) and don't have the same buoyancy characteristics as the X7-100s. They're still good tanks, slightly negative when empty, but the X7's are better. This might be marginal or negligible for some people, especially when comparing to an AL80 with super float at the end. I'm 5'4" and more torso than legs and X7s are much easier to carry due to its height.

 

[Eric Sedletzky]

What about the tall skinny 7 1/4" dia. 3442 120's, same story?
These are actually my favorites.

 

[shurite7]

What about the tall skinny 7 1/4" dia. 3442 120's, same story?
These are actually my favorites.

Same story. It is sad that Worthington is no longer making scuba tanks. I really like the X7 series (80, 100, 120), much more than Faber's.