Build a Hot Wire Foam Cutter

Learn How To Build A Hot Wire Foam Cutter

Learn how to build a hot wire foam cutter for foam and polystyrene. A simple tool powered by a power supply, to help you in your crafts projects.

Start building your own hot wire foam cutter on a budget. It will only take you a few hours and you only need a few parts. As always, remember to be creative and not necessarily do something identical to mine. You will have to use the materials and tools you have available. Always improve the design if you can, depending on your needs.

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If you really need a foam cutter for the projects I’m presenting here on the blog, but you don’t have the skills to build one here you can buy one that I recommend. Scroll down to the bottom for the video tutorial, if you don’t want to read the entire article.


  • Flat wooden board or plywood 70 x 45 cm
  • Wood screws
  • Electrical wires
  • Power transformer 12 v / 2-4 A
  • Two “L” shaped metal pieces
  • 1/4 of an 80 cm in diameter wooden circle
  • Nuts, screws and washers
  • Power switch
  • Cutting wire ( example: guitar string, nichrome wire )
  • A small metallic ring

Wooden Board

You will use this one as the base of your cutting machine. I call it “working table”, as pretty much that’s what it is. Find the center of it and drill the hole to fit the screw. You will secure one end of the cutting wire. Since we will also add a washer, make sure you drill the space for that. For the bottom feet, you don’t really have to use rubber as I did. You can add wood instead. To me it worked well as I had the rubber available. Also… this way the table doesn’t move at all.

DIY Foam Cutter Parts
Foam Cutter Arm

The Wooden Arm

Fixing the arm of the hot wire foam cutter

The way I measured this was to have a 1/4 part of an 80 cm circle in diameter. The reason I made this way, was to allow me to change the cutting angle. Cutting the space for the screw on the entire length, allows me to do so. Before you install this to the wooden board, check for the alignment of the cutting wire. You should have a perfect 90° angle. Once you’ve done this, you can secure it to the wooden board.

The Electrical Part

Before continuing the installation of all the parts, let’s do the electrical. You will need a wire with a connector at the end. This will run from the screw at the center of the board, to the power switch. We will place the switch at the end of the wooden board. The second wire with a connector at the end, will be installed on the wooden arm. Then connect the wires to the switch and secure the cables as you can. The other end of the switch will be used to connect the power transformer.

Power supply needed for a foam cutting machine
Installing a power switch to a foam cutter

The Cutting Wire

This you can make from a nichrome wire, a thin E guitar string, a steel fishing wire. The nichrome wire works the best. Attach it to the screw from the center of the board first. After that use a small ring as in the video. Now connect the wire to the steel spring. Make sure you get the wire tight enough so it will not create an angle when cutting. The reason I use the ring, it’s to be able to remove the wire easy. I do this when I have to cut in the center of the foam. You will see more of this in my future video tutorials.

Now you know how to build a hot wire foam cutting machine. I found it to be really useful in the house. It allows me to create a lot of crafts and decorations. It works amazing for polystyrene and foam. I haven’t tried it, but it should cut plexiglass as well. I hope you will enjoy it, and it will help you in your projects.

Video Tutorial

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