Yup Mud gun was the choice, I would never take the time to TIG weld any exhaust under a car.......Especially coated and OLD *** pipe! Screw that! Lol. Be careful though you don't want to penetrate too far and into the threads. The material where you weld is really thin before getting into them. Also DO NOT put anything in the threads like a Plug or the sensor when welding or you will NEVER get it out! After it cools off, chase the threads and you are good to go.