DIY Hot Wire Foam Cutter

Here is a project that you can build on your own and it makes life a lot easier when you are cutting out areas in your foam plane.  How many times have you used your hobby knife with a dull blade to cut your foam…and you end up tearing out chunks of foam instead cutting a nice, straight, clean line and peeling out the foam after you’re done…I know that my record is poor at best.

Well, if you have some basic soldering skills, and can operate a drill press, you too can build this foam cutter…and to coin a phrase from TV….”and it really really works”!!  It isn’t cheap, but the parts are of high quality, and as everyone knows, you get what you pay for.  Total all-in price is about $90, but for that you will have a variable power (which varies the temperature of the Ni-chrome cutting wire) hot wire foam cutter.  As you can see from the photos, you can bend the wire to makes various shapes which will accommodate anything you may need to put into your foamie, and it will make a clean and precise cut.  It may take some practice, but you’ll quickly gain the ability to make cuts to fit your battery, receiver, servos, esc’s and anything else you can think of.

NOTE:  The wheel collars are used if you wish to control the depth of your cut.  One other item of interest…when you turn off the cutter, the Ni-chrome wire cools quickly..the wheel collars don’t!!!  So watch out for your fingers, and foam.  The collars can get hot enough that while cutting, they will melt your foam, so be aware..maybe put a wooden ruler down as an edge for the collars to ride on….anyway, I’m sure you’ll figure it out.

This all came about when the club was doing a group build of a flying wing.  The wing is all foam and is virtually indestructible.  It required all components to be recessed below and flush to the top of the foam.  Hobby knives were used by most of the builders with some wings areas being cut out better than others….and then we see what one builder did using the hot wire foam cutter.  Very nice, and extremely precise.  Regardless…all our planes fly nicely with, but some of us had to fill in areas that we cut out too large for the battery or servos.

Any SLRCC Club member who may need the use of a hot wire foam cutter is welcome to borrow it.  Contact Don Monteath as he is the proud owner of the cutter.  Contact information is in the members area (roster).

Here is the completed project

Power Supply with Cutting Tool - Finished Project

Inside of Box showing connections

Parts List:

18 Gauge NiChrome Wire

Banana Plug

Binding Post


Lutron Dimmer Switch

Phenolic Sheet Tan

Power Cord

Project Box


Wheel collars