Hot Wire Foam Cutter

  • Post category:DIY Tools
  • Post last modified:October 26, 2020
DIY Hot Wire Foam Cutter - Pinterest Image

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.

The hot wire foam cutter is a tool used to cut styrofoam, 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

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DIY Hot Wire Foam Cutter Parts

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.

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.

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.

Wooden Arm For A Foam Cutter
Fixing The Arm On A DIY Hot Wire Foam Cutter

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. Here you can buy a suitable 12V AC power supply that you can use for your hot wire foam cutter.

DIY Hot Wire Foam Cutter Power Supply
Power Switch For A Foam Cutter
DIY Foam Hot Wire Cutter - Wiring Diagram

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.

Video Tutorial

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This Post Has 4 Comments

  1. Al Cleland

    I wanted to cut some unusual shapes from PVC Pipe and used the information you provided in this article as a basic starting point to avoid the trial and error method of determining wire size and power requirements to make a cutting tool for my purpose. I bought a Buck Saw made of Maple at a Yard Sale minus the blade for $2.00 and a 10ft 14AWG lamp type extension cord from Big Lots for $5.99 I already had a lamp dimmer and a 120VAC60HZ/36VAC3AMP transformer. The Buck Saw was designed for a 30 inch blade, I made my blade from 24 inches of the same 28AWG Nichrome wire you specified and 2 3 inch steel spacers fashioned from a wire clothes hangar. I attached the steel spacers to the wooden frame with stainless nuts and bolts and the copper supply wires to the nichrome and steel with the same plus aluminum clamps made from an empty beverage container. You can buy aluminum washers if you like but the aluminum forma a sacrifical anode and prevents galvanic corrosion in the steel, copper, nichrome junctions they’re good for over 100 hours of use and easily replaced. I put the dimmer switch in the primary circuit of the transformer and the last foot of the extension cord (female end) connected to the secondary. I used the rest of the cord for the supply to the blade. With the dimmer at about 75% (27VAC) across the blade it works like a charm. I thank you for making my design easy to complete. For anyone that might want to use my design I caution you that you might want to use a different connection between the power supply and the blade than I did, as a child, idiot or fool could conceivably plug mine into line voltage which could be quite dangerous and if you live where line voltage is 220V make it 4 times as dangerous.

    1. Thanks so much Al. That’s some really good information to know. It’s nice the way you found all the bits and pieces and put them together. Ohhhh the dimmer sounds like a great idea. This way I wouldn’t need the alligator clip on the wire to change the temperature, as it works well with the dimmer. I’m glad it helped and it works. Good luck on your projects. Best wishes.

  2. Ciprian I. Popica

    I used this one to make my planes models when I visited you remember ? I was in love with this tool so… I had no choice but build one on my own. I have to admit, works like a charm. The funny thing is that it’s so fun to use, that I would cut foam and polystyrene all day lol.

    1. You were using all my foam to make plane wings so I do remember hahaha. I’m happy you have your own now. It’s fun to cut with it I agree. I’m the same when I start working on foam crafts.