Let's remember safety first this cutter gets hot you can get burned. Please be careful and use you head.
Step 1: Getting Started Making a Very Cheap Foam Cutter
Step one obtain a letter C from your garage local craft store etc.
2. Obtain resistance wire I got a 100' roll off eBay for less than 5$ free shipping. Craft store has it also.
3. You need a few feet of wire or even an old extension cord.
4 two screws and a screw driver
5 a spring even a small one from an old click ink pen will work
6. Two alligator clips work best but even clothes pins will work ( yes I'm a junkyard dog)
7 your sons old train transformer any gauge will work
Step 3: Enjoy and Have Fun
I have been using mine for hours playing with the transformer to vary the heat. Hotter cuts the thick foam good for me.
Have fun creating but most important be careful and stay safe. !!