Steel 120 weight observation

[Gregflier]

I had read that the Worthington/ XS scuba 3442PSI X7-120's weighed 38.0 lbs and the older PST 3500PSI 120's weighed 39.2 lbs empty.
Scuba Cylinder Specifications from Tech Diving Limited - 928-855-9400

I weighed two 3500psi tanks empty with valve and they were 39.5 lbs each. I weighed two (brand new) 3442 psi tanks also empty with valve and they were 42-42.5 lbs. All tanks had boots.

The absolute weights might be off because of the cheap scale I used, but I was surprised that the old 3500 psi tanks were lighter. The measurements were repeatable.

Are the new 3442psi tanks built heavier or am I looking at the wrong chart?

Not a big deal, but I'm curious.

Greg

 

[NudeDiver]

Deleted. Nevermind

 

[spoolin01]

Not an expert but so far as I can tell the small pressure rating difference has nothing to do necessarily with tank weight. Many of the HP steel tank models are engineered under various specific exemptions to the DOT 3AA standard, from what I understand, and are lighter.

 

[Leadking]

First understand that different manufacturers' use different techniques in manufacturing. The Worthington cylinders, while still employing the deep draw method, have a thicker "bottom" than some others. This will allow, in the event of water penetration, minor pitting without compromising the minimum wall thickness. Further E or SP tanks are make from a different steel alloy than 3AA cylinders.

 

[Gregflier]

Thanks for the information guys. Does anyone know where accurate cylinder specs can be found for the Worthington X7 120's ?

Greg

 

[spoolin01]

Found this link looking on the Worthington website.

Sea Pearls - Steel Cylinders