This is a pipe bender with pipe size dies. If you bend something besides pipe with a pipe  die, expect it to not work correctly. Mine makes a nice bend with the  sch 40 pipe that it was designed for without using sand.

I get what your saying about the sand, but don't blame the bender because you used the wrong size tubing.

You don't need to use sand when bending pipe w/a pipe bender, just as you don't need to use sand when bending tube w/a tube bender, however if you want to bend the tube using a pipe bender you need to use sand to reduce the amount of deformation and rippling you get w/o sand, as well as the right size tube for the die, i.e. 1-5/8" tube for the 1-1/2" pipe die.  You could also have the smaller pipe die machined to accept a the tube diameter you are using.

I am not blaming the HF bender, I knew going in that it wasn't intended to bend tube, but given the ridiculous amount of money the local 4x4 shops wanted to bend the tube($475+ and I already had a jig for my bends) and the local muffler shops wanted $10-15/bend, the HF bender was the cheapest route.  Besides I figured if it didn't work I would just return it and pay the muffler shop.  It will actually do a good job providing you take your time and don't get in a hurry.

Here is my results w/the HF bender
Flatbed cage and Bumper/brush guard

What happens w/o Sand and exhaust tube:
It looks a little better than it did.  I tried to salvage it by cutting out the ripples and welding in new material, since it was going to be used for inter cooler pipes and not exhaust.  Even w/sand and heat the bend didn't turn out smooth enough for IC piping, so I went ahead and used pre-bent mandrel pieces instead.  Either piece would have turned out O.K. for exhaust, just not that pretty to look at.