Restoring bent metal rods to their original form requires little effort when the correct tools are used. Unlike hollow metal tubing, a solid metal rod transfers heat evenly throughout its body. This allows you to relive the stress surrounding the bent area of the rod by applying heat on and around the bent area. There is a fine line between the amount of heat needed to soften the rod and overheating the rod to a point that it weakens the bonds between the molecules of the rod.
Turn the handle of a bench vise counterclockwise to open the jaws wide enough to fit the diameter of the bent rod. Slide one end of a bent rod in the vise jaws. Align the bent section on the rod with the top of the vise jaws. Turn the vise handle clockwise to secure the rod in the vise.
Close both knobs located on the torch handle of an oxy-acetylene torch clockwise. Start the flow of acetylene to the oxy-acetylene torch by turning the valve connected to the red hose counterclockwise 1/2 turn. Repeat the process with the oxygen valve connected to the green hose.
Turn the red knob located on the torch handle 1/4 turn clockwise. Light the acetylene gas flowing from the tip of the torch handle by setting a striker in the gas flow and pushing the handle of the striker clockwise. Turn the green knob located on the torch handle until the flame coming from the tip of the torch is bright blue with a well-defined inner flame.
Hold the flame emitting from the end of the torch four inches from the surface of the rod, aligned with the rod bend. Move the flame around the circumference of the rod until it starts to glow a faint orange color. Slide one end of a hollow pipe over the end of the rod.
Push the pipe against the rod--in the opposite direction of the bend--while continuing to heat the rod with the torch flame. Continue pushing until the rod begins to move. Stop heating the rod when the bent area is straight with the length of the rod. Allow the heated area to cool for 45 to 60 minutes until loosening the bench vise.