Modat22 wrote in
:

I need to make sure it won't explode and was thinking about letting it
sit in the sun open for a few days then fill it completely with water.

Any other ideas?


My old welding instructor favored running a hose from a vehicle's tailpipe
into the tank and letting the vehicle's engine idle for a while before
starting to weld and continuing to run while the welding was being
performed.

This provided a CO2/CO purge of the tank with an inert atmosphere inside
the tank during the welding process.

He also used this technique when using an OA torch on old oil drums.