Hydro / Tumble Damage?

[BRT]

This is what they said over email

“It looks like that groove is from a tumbler from a tumble done in the past. Our tumbler has a 2” plastic safe guard to protect the cylinders . In all honesty, that tank is fine. The bottom of a steel SCUBA cylinder is close to 4” thick, so no need to worry.”

This tank was born in 95’, hydro in 00 and then hydro last week.

They just don’t care.

4" thick, is it?

 

[TrimixToo]

I am gessing they meant 1/4".

Yeah, maybe.

Steel tanks aren't anywhere near 1/4" thick anywhere, though. The walls are about .150" thick. The one I measured some time ago was something like .015" thicker on the bottom compared to the sides (going by memory). I'd measure the groove and depending on its maximum depth I might reject the tank.

 

[BRT]

Yeah, maybe.

Steel tanks aren't anywhere near 1/4" thick anywhere, though. The walls are about .150" thick. The one I measured some time ago was something like .015" thicker on the bottom compared to the sides (going by memory). I'd measure the groove and depending on its maximum depth I might reject the tank.

If they were only 150 thou thick they wouldn't weigh anywhere near what they do.

 

[TrimixToo]

If they were only 150 thou thick they wouldn't weigh anywhere near what they do.

I measured one (an LP30) before posting, and it was about .150" per one of my dial calipers. I could break out a decent mike and ball bearing and measure it down to tenths, but that seems like overkill.

In 2006, Vance Harlow wrote:

"Acccording to the DOT specs, Steel 72s must have a minimum wall thickness of .164 at manufacture, but tend to run thicker, say, .180 or so. The are usually a bit thicker at the top and bottom. Cut one in two and fell the thickness, and its pretty scary, to think that little bit of metal (most of them started as 1/4" disks of plate steel that were spun into shape) is all that's between you and a whole lot of explosive potential.

Aluminum 80s have a miniumum DOT thickness of .491", and in real life run about .521"."

I'm sure HP tanks have more wall thickness, but I doubt any are .250" thick. .200", maybe.

But the central point is that there is damage to the bottom of the tank, and there is a specification for the maximum depth of that damage for accepting the tank during a visual inspection.

Edit: Actually, what I measured was an LP72. The 30's are smaller in diameter.

 

[rhwestfall]

@abnfrog has a cut open steel teaching aid. Wonder if he could provide a wall thickness measurement.....

 

[davecampbell]

name and shame this crap operation. If that was pre-existing, it should never have gone to hydro, tumble, etc... It should have been mentioned before anything occurred.