Easy to make a spring

To make a spring, we select a steel wire of the desired diameter. Ideally, brand 65g, for lack of suitable for example a steel core from a Soviet-style street aluminum twisted wire. We wind the wire around a round core of a suitable diameter and get a spring blank. On both sides, leave even ends of approximately 50 mm, which are removed after hardening.
We prepare a bath with used engine oil (any one is suitable).

We insert one end of the workpiece into the electrode holder of the welding machine, and close the second to ground. When the spring is heated to a crimson color, the chain opens,
the workpiece is immediately lowered into the oil.

Do not overheat, set the current to minimum. If possible, make several blanks, as temperature is difficult to control.
It is clear that such springs cannot be used for critical products, but for example, for making traps for rodents, repairing delimbers, etc. trifles are quite suitable.