Welding on a car muffler can solve a great deal of problems, from installing a new exhaust system to just fixing a leak. However, it can be dangerous and should only be performed by someone already skilled in the art of welding.
Use a hydraulic jack to secure the car on a set of jack stands. The vehicle needs to be raised in order to allow you the adequate space to work. This contributes not only to the quality of the work, but also to the safety of the process.
Clean the muffler and exhaust areas to make sure that the weld takes well. Any sign of rust should be cleaned or sanded off. Make sure the piece you are welding to the exhaust pipe is a similar size. You can choose to have the exact same size ore do a slight overlap from either pipe.
Gather your equipment, including any additional steel you'll be using to weld the muffler into place. Proper welding safety gear is important. This should include a welding mask, goggles and fire proof apron.
Find something to support the muffler up to the pipe. This will enable you to tact it in place. Double check to make sure it is lined up properly. Then finish the weld all the way around the muffler. It's a good idea to use a high temperature clear (or color, if you prefer) spray paint to coat the muffler and weld area, to avoid rust.
