To bend steel pipe, you need to apply heat evenly to the entire area that you need to bend. The main problem with bending pipe without a tubing bender is kinking the pipe. If the pipe kinks, it will lose its structural integrity. The kink will restrict the flow of water if it is a water pipe; if it is steel pipe being used as electrical conduit, you will have a problem fishing the wires past the kink. To avoid kinking the steel pipe, you must support the walls of the pipe while you perform the bend.
Cover one end of the steel pipe with two layers of duct tape. Secure the loose ends of the duct tape with more tape.
Stand the pipe on end, with the taped end resting on the floor, and fill the first 12 inches of the steel pipe with damp sand.
Pack the damp sand with the tamping rod and add more sand to the steel pipe. Continue the process of filling and packing the sand in the steel pipe until the entire length of pipe is filled with damp sand.
Cover the open end of the steel pipe with duct tape to contain the sand within the steel pipe.
Secure the sand-filled steel pipe in the vise, with the area of the steel pipe you need to bend extending out past the end of the vise.
Light the oxy-acetylene torch and set the torch to burn a neutral flame. A neutral flame will have a blue exterior flame with a short bright blue interior flame that does not emit any black soot.
Evenly heat the entire area that you need to bend by running the neutral flame of the oxy-acetylene torch around the entire circumference of the steel pipe until it emits a low orange glow.
Apply pressure to the end of the steel pipe and start bending the steel pipe; keep applying heat to the bend area while you are bending the steel pipe.
Allow the steel pipe to cool and then remove the steel pipe from the vise.
Remove the duct tape from both ends of the steel pipe and tap one end of the steel pipe on the ground to remove the tamped sand from the steel pipe.
Use the water hose to run water through the steel pipe to remove any sand that remains in the steel pipe.
Wipe the pipe dry with a clean rag.
