Steel reinforcement bar -- rebar for short -- is an essential ingredient of concrete foundations, footings and walls, and it has many other uses as well. Pros often bring a rebar bender with them to a job site, but if you need to make a only few bends, there is an easy way to do it without a professional's bender.
Vise and Pipe Method
You can bend 1/2- and 3/4-inch rebar quickly and easily by using a vise and a length of 1-inch steel pipe. Mark the position of the bend on the rebar, then insert it into the vice with the mark aligned with the jaw. Tighten the vise, then slide the pipe along the other end of the rebar until it's just short of the mark. Stand in front of the vise and pull the pipe toward you to bend the rebar. The longer the pipe, the more leverage it will give you.
If you need to make a bend near the end of a length of 3/4-inch rebar, you may have trouble doing it while it's cold. Using a propane torch to heat the joint makes the steel malleable and easier to bend. Be sure to wear goggles and protective gloves -- the rebar and pipe will get hot.