Styrofoam Cutter From Scrap

Early this winter, my father wanted to isolate from the cold a metal door in the back of his workshop using styrofoam panels. To cut them properly, he wanted to use one of those tools with a metal wire that heats up and cuts neatly through the polystyrene without leaving rugged edges or scattering crumbs all over.

We gave a quick look at online stores, but nothing was available for less that 20 or 30 Euros. Being made of a simple iron wire, I chose to give it a try and assemble some (literal) garbage: an iron wire from an electric heater’s resistance, a push-button from a cheese-grater, and a scrap MDF panel from who knows what.

For the power of the resistance I had no frame of reference, so thought I could start with around 20W and gradually see if any increase or decrease was necessary. I cut the wood to be as large as possible so to have a length of wire that would be comfortable to use with thicker panels too. At that length, the iron wire measured about 5 Ohms of resistance, which at 12 volts would output approximately the power I wanted to start with.

I hooked up a 12V power supply and voila: the resistance happened to be perfect and worked neatly at the first try. Here’s my cousin using it to slice some of the panels for the door: