I'd probably need to weld a threaded bung into the bottom of the tank for a condensate drain. I always purge a gas tank with CO2 or nitrogen before dong any welding- - - -no oxygen- - - -no boom!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!