>Muffler shop benders are compression benders, unless the shop has a mandrel
>bender.  Compression benders produce wrinkles on the inside of the bend,
>most people would find this unacceptable for appearance reasons.

Man, I can't remember the last time I saw a wrinkled exhaust bend!
Modern benders produce an indentation on the inside of the bend,
causing some restriction in the pipe there, but no wrinkles.

No problems getting 3" pipe mandrel-bent here...
--
Andrew Grebneff
Dunedin
New Zealand
Fossil preparator
<andrew.grebneff@stonebow.otago.ac.nz>
Seashell, Macintosh, VW/Toyota van nut