[VAC] Re: Polishing Aluminum Tanks

[Tuna <rctowns@xxxxxxxxxx>]

Tanks containing compressed gas can fail (read "explode") if they have been
exposed to extreme heat (like in a garage fire) or shock (bounced off
concrete from a height). Scuba tanks (about which i know something) must be
visually-inspected (for rust/corrosion inside) once per year; and
hydrostatically (pressure) tested every five years. Following the
hydrostatic test, the tank's 'shoulder' is stamped with the month/year of
that 'hydro'. If a tank doesn't pass inspection, it is 'condemned', and the
test facility is supposed to cut the bottom off the tank. They'll give it
back to you so you can salvage the valve. Different tanks for different
contents apparently have different visual and hydro requirements.

Extremes of heat and shock 'stress' a tank in ways that may not be
detectable by visual inspection. There have been a few notorious incidents
in which people have sent off scuba tanks to be powder-coated or enameled,
and were subjected to high heat in the process. The next time these tanks
were filled, some of them exploded - killing or dismembering the unfortunate
persons running the fill-station.

I would be extremely careful about doing anything to a compressed-gas tank
that might compromise it, including polishing an old, rusty or oxidized lpg
tank. "De-Rusto" makes a terrific 'rattle-can' spray paint in Aluminum color
that I've used to pretty-up some old lpg tanks.

Tuna