Maybe, but would have to torque the hell out of them with a set of wrenches. Hand tight isn't enough. When full of media, would the weight then cause enough change in shape to create a leak? Or maybe use threaded bulkhead with a dab of silicone on threads like tephlon/plumbers putty works? I just got four more barrels for free to work with. These are black not blue....but so what. They are safe based on contents, and I like black better, holds more heat.