Has anyone ever used this tailpipe expander before?

Auto Body Toolmart Tailpipe Expander

it seemed to work as advertised.

bought it 30-odd years ago and used it twice. not to "expand" the exhaust pipe to a larger size, but once to un-crimp a clamped pipe (the crease from the clamp) and once to straighten an out of round pipe.

it works for those purposes.

if you're looking to expand to the next size (to flare one pipe Inside Diameter to fit over the other pipe Outside Diameter), it might work.

never needed to use it for that, was wary it would tear the pipe metal.

I used a $10 one from Harbor Freight on aluminum pipe and it worked great.

Hillary Clinton has had one going for a while now!

I've used mine several times with mixed results. They will not expand an exhaust pipe so that it could fit over another pipe but it will like Bart said remove the creases or dentations produced from pipe clamps.

I tried to expand a 2" pipe to fit over another 2" pipe and I had to use me air impact gun and greased the heck out of the expander and pipe.