bonded?

[Moogyboy]

Just to satisfy my curiosity, and irrelevant to anything I'm doing:

I remember reading something somewhere a long time ago about "bonded" tanks, I believe with regards to how far they can be legally filled or something. I want to say that this referred to steel tanks, and had something to do with a "bonding wire". Eh? I have no idea what the concept of bonding is when applied to scuba tanks; could someone shed some light?

cheers

Billy S.

 

[derwoodwithasherwood]

Are you by any chance thinking of "composite" cylinders? Usually a thin aluminium shell wrapped with kevlar or fiberglass, they have a lifespan of 15 years and must be tested every 3 years (in Canada anyway).