An exhaust pipe expander is a a specialist tool used to expand sections of exhaust pipe. Exhaust pipe expanders are usually used to flare one end of a pipe so that another section of pipe with fit inside securely.

Exhaust pipe expanders are used by inserting the tool into the pipe to the area which is to be expanded. Then the hexagonal nut is rotated to expand the tool which pushes the pipe wall outward to expand the pipe. Depending on the pipe thickness an air impact wrench may be required in order to exert enough force to expand the pipe. Heating the pipe prior to expansion may also help.