Hot Wire Foam Cutter

Hey guys, I am working on some foam models right now and needed to be able to cut larger pieces of foam so this weekend I designed and built a hot wire foam cutter table.

I wanted to share the process because it’s a really easy weekend project and it cut through 5 layers of glued together foam sheets like butter! You’ll end up with a powerful tool that will help speed up your foam modeling. This version can cut make cuts up to 28" tall and 16" wide but you can adjust it to be as large as you want. You can cut horizontally or vertically, it’s easily adjustable with the corner clamp on the arm that holds the wire, and the hole thing breaks down and fits in the base.

I hope the pictures give more detail on how it works but feel free to ask any questions!

Cool build, and nice pics! The tuner bit for tightening is a neat idea.

How is it hooked up to a power supply?

Thanks CRVaughan! It’s hooked up from those red and black terminals on the guitar tuners. Those are “banana jacks” and I’m using banana leads that are connected to a variable bench top DC power supply.

This is awesome!
Thanks for sharing the build steps, definitely something I need in my garage for projects! :slight_smile:

Thanks mcpbowman! No problem at all, I hope the build steps are helpful if you decide to build one for your garage!

Is the heat variable with this build? Easy to make it so if not?

Just curious, what are the specs of your power supply? I imagine 12VDC? How many amps?

It’s funny, because I’ve been contemplating building a wire cutter over the holidays. Good timing!

Hope everyone in the USA had a great Thanksgiving, and outside the USA, a fantastic Thursday!

MK19, the heat is variable, I’m using a variable DC bench top power supply, you can vary the temperature in the wire by increasing the amount of current going through. Wire lengths and gauges will vary the amount of current needed to heat to the same temperature.

Mr-914, glad you’re thinking of building one too!

I have been deliberately been shying away from giving exact electrical details about this project for safety/legal reasons because I don’t want anyone to hurt themselves. It’s impossible for me to know anyone’s experience with electricity, and even something simple like this can easily be fatal. Sorry for this likely unsatisfying answer.

That said if anyone would like to PM me for help with the electrical portion of their project, I’m more than happy to provide some advice.

Here is a list of electrical safety tips that may be helpful for this kind of build:

  1. Never touch the cutting wire when it is plugged in to anything, even if it is off. Disconnect all wires from the machine before changing, adjusting, or touching the wire.
  2. Take off all jewelry (wedding rings, watches, bracelets) while using the foam cutter.
  3. Do not operate this with wet hands, even a small amount of sweat can be extremely dangerous.
  4. Wear safety glasses (the wire can snap) and an fume filtering respirator (foam fumes are bad news), operate this outdoors for lots of ventilation if possible.