Loads of alternatives here - Chemical metal (needs to be thoroughly degreased), fill the holes with solder or braze, weld over them, drill out and fit a self tapper with a bit of sealant on it (One of my central heating pipes was bodged like this for years when I stuck a nail through it....) - grind off the excess thread on the inside. Bigger holes? use the old fashioned saucepan repair. A nut and bolt. two steel washers and two rubber washers.