I bent my steel and aluminum fuel lines, both 3/8" (return) and 1/2" (feed) using an el cheapo Harbor Freight bender.
I had kinking problems until I used some fine emory cloth to 'clean up' the casting on the face of the 'shoe' or 'follower' (the part of the bender that actually slides along the top surface of the tubing). I also found that rounding the forward edge of the 'shoe' prevented it from binding and denting the pipe. Lightly greasing the tubing and/or 'shoe' also helps (but NOT the area where the tubing is clamped into the bender).
For larger diameter (over 2") bends, the spring type manual bending method (i.e. slides over the tube to prevent kinking) works OK.
FFR Roadster #3440, No donor build. \'99 Cobra alum IRS with 3.55\'s, powered by Vortech SQ blown, 428 HP/444 ft-lb Levy Racing Stage 3 EFI 306, T5Z, CoolParts steering shaft, Wilwood 13\" front and 12\" rear brakes, SN95 front susp w/ FFR lowers, FR 15-1 rack, 17x9 and 10 Image wheels, Autometer Ultra gauges, Levy Racing Stage 2 suspension. Porsche Red with White Stripes, courtesy of SRP\'s fine work.