How to Make a Hotwire Cutter...Cheap!




About: Retired, doing art work now. Great. Have the time and the money to spend doing what I want to do.

To enter the weekly challenge for using wire, I decided to write up my very first hotwire project.  I did this about 15 years ago, and realized now how useful it can be to those who would like to get their feet wet in the hotwire arena.  I have since made more substantial, electrically powered hotwire machines (see:, but this was the first, was very inexpensive, and was a starting point for me. Maybe it can be for you as well. Total cost can be way less than $20.

Step 1: Concept and Materials

At work one day, I was challenged by a statement from a co-worker: "You need to find a way to recycle some of this styrofoam."  (We received shipments that needed refrigeration, and they all came in dense styrofoam containers).  Being a self proclaimed artist, I thought it would be fun and challenging to be able to reuse said boxes and containers.  As chance would have it, I stopped by a Michaels and was guided to the floral section where there was this "Wonder Cutter." (See:   It was a device that was used to cut or slice floral foam, and it did that by heating a wire that could be used in the cutting of the foam.  Just what I needed. Please be aware that the device shown on Amazon is the latest version of the tool I used.  It is different in the switching, and case.  It should be "hackable" though, but check it out first.

Step 2: Build Table/Box to Hold Cutter

I built a box to surround the wonder cutter, and provide a "table" surface so that shapes could be cut out of the styrofoam. It is a pretty crude piece, but it did the job!

Step 3: Bend Existing Frame to Fit Table/Box

As you can see, the frame for the hotwire is bent so as to provide an arm to fit the table. This way, the wire is held vertically at a right angle to the table top.

Step 4: Cutter Is Held in Place With a Strap and Support

I designed a support as shown, and used a piece of metal strapping to surround cutter. The strap is secured behind the support with a wood screw that tightens the strap and holds the cutter in place securely.

Step 5: Install Batteries, Start Cutting

Batteries supply the electrical power necessary to cut the styrofoam.  I have included a gallery of early projects in the next step.  This table has been in storage for at least 10 years, but when I closed the switch, the wire actually got hot enough to cut the piece of styrofoam, as shown in the pictures.  And this unit could be put back in to use as is.  It does cut pretty slowly, however, but I did use it for a few years before I upgraded!



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    6 Discussions


    7 years ago on Introduction

    That is awesome. I was just reading about methods of cutting foam, and this one looks just about right for me. (I was on the verge of borrowing a friend's electric carving knife. Possibly never to return it.)

    1 reply

    7 years ago on Introduction


    Another way to make one of this is to use a metal guitar string (the skinny "E") and an old power supply for a router/modem/house-hold item or computer PSU.

    4 volts/500 milliamps should do...

    1 reply