Aluminum Fuel Cell/Tank crack repair

I have had excellent results with aluminum repair with something called "Devcon". The can is at work, so I can't give anymore details. In dry applications, I've never had the stuff crack or lift off. Put it on like Bondo and file it smooth. Don't know how it would do with fuel. If the holes are 3/16" diameter or less, I would 'buck' an aluminum rivet in the hole. If there is a local EAA Chapter (Experimental Aircraft Assoc.) near you, they might could help. Airplanes usually have aluminum tanks and these guys sometimes weld their own.