[s-cars] RE: Mandrel Bend Confusion

[QSHIPQ at aol.com]

A couple observations Roberto.  First, mandrel doesn't require the insertion
of a device, it can be done by moving the bending tools to accomodate the
metal stretch.  It can also be done by inserting sand into the pipe before
bending.  Another way to make a darn close mandrel bend is to use a regular
bender with 1" larger dies.  This ovals thick walled tubing instead of
crimping it.  I had several 3in systems (including downpipes) built this way
by a race exhaust fabricator here in Chicago.

I've also noticed several vendors of 3in systems (and audis own 2.50 singles)
tend to crimp pipe as it goes over the center crossover brace = not good.
Remember too, that less bends is better, and that any crimp almost negates
the use of bigger pipe alltogether.

HTH

SJ