Hot wire foam cutters apply electrical current through a tightly strung monchrome wire making it very hot.  When slid along a template such as my radiator shape or a wing rib, it slices through foam like a hot knife through butter.

While one can always simply carve the foam to the desired shape without a hotwire cutter, anytime you have a very specific shape or need to produce multiple foam pieces that are all identical, the hotwire foam cutter really pays off. 

In my case, it’s only one item and I could easily have carved and sanded it to the desired shape, but I already had the wood bucks so why not?  It will make it so much easier.

The build is very simple.  I used 1″ PVC with 90 degree elbows at each end. 

Eyebolts were attached at either end that accepted one wire from the power supply and also was used to string the monochrome wire.  I used 22g monochrome wire I bought from Amazon.

I had a variable electrical power supply I used for some crazy idea experiments of the past laying around so I planned on using it to provide the 12V at 5 amps.  Unfortunately, it would not go that high so I bought one from Amazon.

The wires run inside each end and come out together at one end and make their way to the power supply.  The monochrome is stretched across the back-prebowed 1″ PVC.  I heated it with a heat gun while bowing it backwards.  Be careful not to heat it up to much or you will get a kink like I did.  I caught it quickly though and let it cool, so no real damage was done.  That way when you attach the monochrome wire, pull it real tight so the PVC frame straightens itself out thereby keeping tension on the wire.  This guarantees the best and most true cut when following your template.