Simple questions on tank age...

[SubseaSports]

Just the picture in my mind.
Yes, the tank to valve oring. Its was steel tank, so the flange is beveled thus it had somewhere to go. AL tanks, not so much.

Orings will eventually take a set, harden and leak and do weird stuff.

 

[Gone for diving]

Its was steel tank, so the flange is beveled thus it had somewhere to go. AL tanks, not so much

On some of those style tanks you need to use 1 dash# lower, it will fit tight, but then it will not squeeze out of the taper,