Build a DIY hot wire foam cutter on a budget. An amazing tool powered by a power supply, to help you with your foam or polystyrene crafts projects.
Start building your own hot wire foam cutter on a budget. It will take you about two hours and you only need a few parts. Remember to be creative and use the materials and tools you have available. The hot wire foam cutter is a tool used to cut foam, polystyrene, plexiglass, etc. The device works by passing low voltage electricity through a Nichrome wire, causing the wire to heat up to about 200°C. The heated wire will be used to cut the foam and the other similar materials.
How To Make A Hot Wire Foam Cutter
1. Supplies
- Flat plywood board: 70cm x 45cm
- Plywood arm
- Two “L” shaped metal pieces
- Wood screws
- 12V AC Power supply
- Electrical wires
- Power switch
- Nuts, screws and washers
- Nichrome wire
- A small metallic ring
- A small spring
- Alligator clip ( optional )

2. What Is The Best Hot Wire Foam Cutter ?
The best hot wire foam cutter is the one you build. It’s also the cheapest considering that the only things you may have to buy are the power supply and the Nichrome wire. Think about the desired size of the tool and the projects you want to use it for. The hot wire foam cutter described in this article was designed to work well for most of your projects.
3. Making A Working Table For The Hot Wire Foam Cutter
Cut a flat plywood board to 70cm x 45cm ( 27.5″ x 17.7″ ). You will use it as the base of your foam cutting machine. I call it “working table”, as pretty much that’s what it is. Find the center of it and drill a hole to fit the center screw. This will secure one end of the cutting wire. Since you will need to add a washer, make sure you drill the space for that as well. For the bottom feet, I used some pieces or rubber.
4. Fixing The Adjustable Arm
I used a 1/4 of an 80cm ( 31.5″ ) circle in diameter. The reason I made it this way, was to allow me to change the cutting angle. Cut a space for the screw to pass, on the entire length of the arm. Before you install the arm to the working table, 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 working table.
5. Hot Wire Foam Cutter Electrical Wiring Diagram
You can see the basic wiring diagram in the photo down bellow. The wiring contains three parts: the power supply, the electrical wires and a power switch. In the electrical diagram I have the switch installed on one wire. The switch I had available was made to use both 12V DC wires.
6. Installing The Nichrome Wire
Use the video tutorial to watch the step by step instructions of how I connected the Nichrome cutting wire. I personally tried other materials, but with bad results. Mostly because the other cutting wires will not last too long. The length of your Nichrome cutting wire, depends of the power output of your power supply. For the one I used, I found that about 30cm – 40cm ( 11.8″ – 15.7″ ) will do a great job. It will not heat in excess, but hot enough to cut the thick polystyrene or foam.
Connect one 12V wire to the end of the Nichrome wire connected to the working table. The other 12V wire goes up on the arm, and connects to the other end of the Nichrome wire. Use an alligator clip on this wire if you want to adjust the heating temperature of the Nichrome wire. If you want it to heat less, connect the alligator clip right at the end of the Nichrome wire. If you want it to heat more, move the alligator clip down on the cutting wire. Now the best way to test the foam cutter, is to use it for something. Here is the first unicorn decoration I made using this hot wire cutter.
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