If you need to add a flare to a piece of tube and you don’t have a pal at the local exhaust shop willing to flare it for you, you can buy a cheap tool that will flare most pipe. The results of using this exhaust flaring tool vary with experience and what you are trying to do with it. We have had the tool in this picture for several years, and it is showing some wear, but it still works as well as anyone can expect. To flare or bring oval’d exhaust pipe back to round, insert the tool in the pipe and tighten the black driver portion with a flat for a wrench. Once things get tight you can whack the black driver portion with a hammer a time or three and try to tighten it some more. Rinse and repeat. You will have better luck with the pipe still on the vehicle or held firmly in a vise.