When bending tubing you have to be careful not to crimp the tubing. A crimp is a bend that went too far and the tube wall collapsed. You can not bend a crimped tube straight again. The extreme bend causes the metal to crystallize at the bend point and will most certainly leak. If you crimp the tube – replace it – especially if it is a gas line. Tubing and pipe will only bend so far before the walls collapse. The minimum bending radius for pipe depends on several factors like diameter and wall thickness of the tube but can generally be given as 3 times the outer diameter of the pipe for up to ½ inch tubing.
Hand Bending Tool
You should always use a tubing bender to shape pipe. To not do so is to court disaster. The most common bending tools are the external spring bender (what I used) and a bending machine or hand tool. These tools will help ensure that the minimum bending radius is not exceeded. For more info on this topic, CLICK HERE.