How bad is the pitting on this tank?

[Tug]

Next question!

How does one know what kind of alloy the tank is? the SP14157 , or that #### aluminum alloy that people wont fill anymore?

check the sticky...

http://www.scubaboard.com/forums/ta...66-my-cylinder-made-bad-alloy-aka-al6351.html

 

[Jax]

Next question!

How does one know what kind of alloy the tank is? the SP14157 , or that #### aluminum alloy that people wont fill anymore?

Thanks, guys!

This a perfect example of a question poorly stated. :blush: But thanks, Wookie, for some excellent information!

How does one know of what their cylinder is made, other than the obvious steel or aluminum? Just because of who is the (purported) manufacturer?

For example, my two HP100s are Worthingtons (I'm told), but are stamped XS Scuba. XS Scuba is the Worthington dealer, as I understand. But my Catalinas and Luxfers are stamped Catalina or Luxfer.

Seems like you have to have additional info, like what was listed in the sticky Lewis posted, to really know what you have.

 

[halocline]

Thanks, guys!
How does one know of what their cylinder is made, other than the obvious steel or aluminum? Just because of who is the (purported) manufacturer?

For example, my two HP100s are Worthingtons (I'm told), but are stamped XS Scuba. XS Scuba is the Worthington dealer, as I understand. But my Catalinas and Luxfers are stamped Catalina or Luxfer.

Seems like you have to have additional info, like what was listed in the sticky Lewis posted, to really know what you have.

You just have to be able to decipher the markings on the tanks. 3AL tanks are aluminum, 3AA tanks are steel made with a specific steel alloy and to specific structural requirements, and the SP (special permit) tanks are made with different specifications (maybe a different alloy, but I suspect its the same steel alloy but not to the same structural requirements) that typically require the renewal of the permit periodically. I assume that's because the SP tanks typically have a higher service pressure for similarly sized tanks as the 3AA tanks, and (a guess) are thought to have a somewhat lower margin of structural safety. The service pressure to size/weight ratio is the main appeal of the SP tanks. Ever pick up a faber 3AA HP100? Not fun...

The tank's manufacturer is always indicated somewhere in the markings, and there just aren't that many manufacturers. On some tanks the original hydro is performed by the manufacturer or a contracted firm, and this can tell you who built it. On my walter kidde LP72, it never says "Walter Kidde" but the original hydro stamp has a K in a circle, and the serial number begins with "AWK". I think the tank had a big Dacor sticker on it, but that just means it was branded as a dacor tank, like your XS scuba tanks. A good place to find a simple yet reasonably thorough explanation of the markings is in the Vance Harlow regulator book. I'm sure there are some websites as well.

 

[Tug]

There are tables out there that describe all the markings. If you're as interested as you seem, pick up a copy of PSI's book. I think it's called Inspecting Cylinders or something like that.... Better yet take a visual inspection class.


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