We wanted to build a hot wire to enable us to cut shapes neatly through polystyrene sheets. Originallythe device was built as a toy for the children but we also used it in other projects. We cobbled it together using pieces of laminate flooring and scrap wood. The transformer is an old computer power supply unit. The only element we purchased was the wire.
The device and the T-shaped guide on the right
At the back, a sliding element allows to adjust the temperature
Inside view: the further the sliding element on the right, the longer the portion of the wire in the circuit
The computer PSU on the floor
The attachment of the wire allows to adjust the tension
Cutting at an angle
A cone is cut by turning a block of foam around the pin