1/2 inch valve

[John C. Ratliff]

This is my favorite Mythbusters episode on scuba tanks.
[video=youtube;NkhtTPU9KjM]http://www.youtube.com/watch?v=NkhtTPU9KjM[/video]

SeaRat

 

[Akimbo]

Has anyone seen a video of a steel tank shot in the side? My guess would be a seam split resulting in an explosion rather than a rocket. Might depend on the ammo???

BTW, the above video would constitute an illegal modification to the cylinder.

 

[Luis H]

Has anyone seen a video of a steel tank shot in the side? My guess would be a seam split resulting in an explosion rather than a rocket. Might depend on the ammo???

BTW, the above video would constitute an illegal modification to the cylinder.

DOT (3AA, 3A, 3AL, SP, etc.) tanks are seamless. There are several fabrication methods, but seams are not allowed. They are formed from a single plate (the most common steel fabrication), a solid slug (the most common aluminum cylinder method), or spuned from a seamless tube (Asahi steel tanks). The codes do not allow seams or joints.

You can not have any welding or any other form of joining on these types of DOT cylinders.

The forming process of the neck (a spun type of process) can create what has been described almost as fold, but it is still a forming process of homogeneous metal, not the joining of metal creating a seam.

I have seen some of the old Cousteau (French) cylinders that were spiral rolled formed, from a sheet of steel and welded. Very visible weld seem. That is not an approved fabrication method for light weight DOT cylinders. I have designed heavy high pressure industrial (ASME code) cylinders that involved welding during fabrication, but those are different code and higher safety factors.

 

[Akimbo]

Seam split was a misstatement. It was just to say that a vertical split would likely occur. Here is a video of steel cylinders being made:

[video=youtube;EzVogfVxXPc]http://www.youtube.com/watch?v=EzVogfVxXPc[/video]

 

[Luis H]

I figured you knew, but I wanted to make it clear for the benefit of other.

Thanks for the video. That is always a good one.