A bending spring is used for making curves in plastic pipe, or for pipes made of soft copper. The tubes are bent by sliding a bending spring with the correct diameter in the tube, so that it can be bent without causing a kink.
A bending spring consists of a steel coil spring, with the windings tightly against each other.
For bending PVC installation pipes for electrical installations, inner bending springs of 5/8 and 3/4 inch (16 and 19 mm) are mainly used. A spring with a length of 0.8 - 1 m. is usually used for this purpose. An eye is located at one or both ends of the spring. You can attach a piece of rope or installation wire to one such eye, so that the spring can be pulled out of the tube after bending, even with long tubes.
