Stainless steel exhaust resists corrosion and lasts substantially longer than a standard steel exhaust system. This corrosion resistance makes the stainless exhaust pipe more difficult to weld. Both MIG and TIG welding processes will weld the pipes together, but a TIG welder will provide a cleaner weld and give you more control over the weld puddle, so that welding the thin walled tubing is easier and you have a solid weld that does not leak.
Hook up the bottle of argon shielding gas to the 110v TIG welder, turn on the valve located on the top of the bottle of shielding gas and check the connection between the bottle of shielding gas and the TIG welder.
Put on your welding helmet and thin leather TIG gloves.
Secure the stainless steel exhaust in the pipe hangers, allowing a 1/32-inch gap between the ends of each pipe.
Inspect the area around the weld joint for combustible materials, pay close attention to gas lines and place the fire extinguisher at arm's reach before you start welding. Do not weld anywhere near the vehicle's fuel lines.
Align the tungsten of the TIG torch with the weld joint, lower your weld and start the arc of the TIG welder by touching the surface of the weld joint with the tungsten and lifting it slightly above the surface of the weld joint.
Feed the .035 304L filler rod into the weld joint as needed to build a small tack on the weld joint. Repeat the process to create three additional tack welds around the weld joint.
Remove the tacked stainless steel exhaust pipe from the pipe hangers and slide the exhaust from underneath the vehicle.
Place additional tacks every 1/2 inch around the weld joints that you tacked together in Step 6. This will hold the stainless steel exhaust in place while you seal the weld joint.
Weld the tacked stainless steel weld joint solid by working the weld puddle around the weld joint, adding filler rod as needed to keep the weld joint solid.
Allow the weld joint to cool before you install the welded pipe under the vehicle.