Welding exhaust pipe tubing can be difficult due to the thin nature of the pipes and the materials they are crafted from. Once you know what to expect from exhaust pipes, however, welding them becomes significantly easier. Exhaust system repairs that require welding don’t generally take very long to complete, though care must be taken to ensure that there are no holes left in the exhaust system due to melting or gaps in the weld itself.
Step 1 – Place the exhaust pipe tubing in its place to check its length. Mark the pipe with a pencil or marker to indicate where it needs to be cut to fit the exhaust system it will be connected to.
Step 2 – Cut the pipe or grind it to a smooth end. If cutting the pipe, use the de-burring tool on the pipe cutter to remove an internal burr or crimping that may result from the cutting. Use a pipe expander tool to increase the size of one end of the pipe as needed if the pipe you will connect it to is slightly larger than the pipe you are using.
Step 3 – Position the exhaust pipe tubing in its correct place again, securing it with the pipe clamps. Check the position of the pipe from several angles after clamping to ensure that it is aligned properly with the existing exhaust pipe you will weld it to.
Step 4 – Turn on your welder and set the voltage and gas flow rate appropriate for the metal and filler wire you are using. Lower your welding mask before making an arc on the welder.
Step 5 – Create three or four spot welds an equal distance apart on the pipes. These welds should be approximately 1/2 inch to 1 inch wide. The spot welds will hold your pipe portions in place during the final weld and will also eliminate the need for a continuous weld around the pipe, which would increase the chances of overheating.
Step 6 – Weld the pipe working from one spot weld to the next. Work at a slow but steady pace, moving the welding bead a short distance at a time. This reduces the need for additional passes, which create layered welds that are more likely to become brittle.
Step 7 – Continue working around the pipe, shifting to a new position as needed when you reach each spot weld. Stop welding once you reach the spot weld that you started your original weld from.
Step 8 – Shut down your welding machine and allow the weld to air-cool. Once the weld has cooled and is secure, remove your pipe clamps.