Toaster Foam Cutter

This weekend I did a small project to learn a little more about how the heated wire part of the foam cutter will work. I happened to have an old toaster lying around and after reading an article about toasters at HowStuffWorks, I knew that they used the same concept. The article from HowStuffWorks is available here:

HowStuffWorks - Toaster

Both toasters and foam cutters use something called nichrome wire. When a current is put through this wire it heats up. This is how a toaster heats up a peice of bread and how a foam cutter is able to slice through a peice of foam. In the picture below, you can see the nichrome wire. It is wrapped horizontally around the sheet.




I removed the small circuit board from the toaster. This is what controls the timing and puts the current through the nichrome wire. The blue and red wires connect to each end of a run of nichrome wire.



Next I tacked two short peices of 2x4 on the ends of a 4' 1x4. I mounted a peice of 1/4" dowel on the tops of the 2x4s for points to mount the ends of the nichrome wire.



I mounted the toaster circuitry to one of the ends and added a switch to the power cord so that I could turn it on and off. I kept the circuitry in case I wanted it later, but it turned out I could have done without it. The only purpose of the toaster's circuitry is to control how long the heat is applied to control how done the toast gets. In my application I just wanted to wire to stay hot as long as I have the switch on. I rigged the circuit so that it would stay on as long as power was applied through the switch.



Below you can see the entire machine. The nichrome wire is strung from one dowel to the other and connected to the blue and red leads from the toaster circuit.




Below is a video of the foam cutter in action. As you can see when heat is applied, the wire instantly sags 2" or more.

Toaster Foam Cutter Video

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