I would like any secrets to bending exhaust pipe without crushing the pipe. I have a hand operated pipe bender. Tried sand filling without any guidance or luck.

You can't do it without a $$$$ mandrel bender. Best bet is do it like the pros and buy mandrel pre-bent 180deg pipes and cut and weld the curves to any shape you want.

See here and here and here.

We all call it exhaust pipe sometims but is really exhuast tubing and you have have a pipe bender. Pipe benders won't bend tubing without crushing it.

In the 60s they use to fill the pipe up with sand and weld caps on both ends to keep it in but its hard to bend a 2.5" x 4" foot pipe with sand in it but if your going to do it heat it with a torch it will make it easer.

J.C Whitney has the mandrel bent pieces availiable in regular mild steel or aluminum coated, very reasonable also.

Vince

"2.5" x 4" foot pipe with sand in it but if your going to do it heat it with a torch it will make it easer."
Be sure that sand is real dry. any moisture will turn to steam and could blow on you. We used to make exhaust systems for prototype cars with sand and weld shut. The sand has to be packed in slow and tight. We used the same sand over and over and kept it sealed to keep out moisture.