Welding stainless steel pipe requires a process that allows precise control over heat and weld puddle formation. Tungsten inert gas (TIG) welding provides the precision heat control required to form a strong weld without warping the pipe. A proper TIG weld will melt into both sides of the weld joint while not blowing into the inside opening of the pipe. Test welding two pieces of stainless steel pipe will ensure the proper weld settings and ensure the weld does not enter the interior of the pipe.
Set one piece of stainless pipe onto a pipe vice. Loop the vice chain around the pipe. Slide one end of the pipe two inches past the edge of the vice. Hook the chain into the vice catch. Turn the vice handle clockwise to lock the pipe in the vice.
Run an angle grinder with a hard wheel around the end of the vice to place a 15-degree bevel on the end of the pipe.
Remove the bevelled pipe from the pipe vice. Repeat the process to place a bevel on one end of the second piece of pipe. Leave the second piece of pipe secured in the pipe vice.
Push the open end of the hose running from a gas regulator into the non-bevelled end of the pipe secured in the pipe vice. Cover the end of the pipe with duct tape to hold the pipe in place and seal the pipe. Connect the regulator to a bottle of argon gas. Turn the valve handle counterclockwise to start flowing gas into the pipe.
Set the bevelled end of the first pipe against the bevelled end of the pipe secured in the pipe vice.
Place a combination square across the two pieces of pipe. Ensure both pieces of pipe are sitting even with the bottom of the combination square blade.
Turn on a TIG welder. Hold the TIG torch in the weld joint. Activate and hold the torch in the weld joint for two seconds to tack the pieces together. Rotate the pipes 1/4 turn. Place a second tack weld in the weld joint. Repeat the process two more times to place four total tack welds between the two pieces of pipe.
Seal the open end of the pipe with duct tape.
Align one end of a piece of stainless steel filler rod with the weld joint. Activate the welder. Move the TIG torch and the filler rod together along the joint to weld the pipes.
Allow the welded joint to cool before removing the pipe from the pipe vice.
Use proper welding equipment to protect yourself during the TIG welding process.