Try inflating a tubeless tire on the rim and use bubble soap to check for leaks around the rivets and bead area. I'd suggest sandblasting the inside of the rims and coating them with epoxy paint or fiberglass resin as a sealer if there are some seep leaks.
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!