Any good contact glue should work but you might try heating the SS corney with warm water first to about 100F. The colder SS seems to keep the glue from setting up. Goop works if you smear it on the rubber liberally. Turn the keg upside down, apply lots of glue, set the keg down on the floor upside down, put a couple of bricks on it for a day. The excess glue that squeezes out can be removed by rubbing it with your fingers and peeling it off.