Hot wire cutter (DIY)

Hot wire foam cutter Image

The Result: Hot wire foam cutter

In this post, I will explain the process of how I made a cheap hot wire cutter.

  • It can be used to cut through Polystyrene, foam.
  • It runs on 12 volt DC, I used a Battery eliminator circuit to provide constant power
  • The filament is from a cheap fish tank water heater coil

The holder is an oven’s tray handle thingy. My mom uses it to load baking trays into our oven (On condition that I return it after use :p ). I used two very long wires which connect to the heating filament and make a closed circuit when connected to a 12 volt DC power.

Type of Frame

Wire cutter's frame Image

Wire cutter’s frame

Oven tray handle that I used for the build. it was pretty sturdy and provided good dexterity when I was working on the foam.

But if you don’t have that, you can use pretty much anything Y-shaped like:
Hacksaw, It can be done, but the frame was a bit heavy for me

Cloth Hanger Image

Cloth Hanger

Cloth hanger. It needed a little reinforcing.

I bet it could be made out of wood too, but that would require a lot of work.

If you use a cloth hangar, its better if you reinforce it because the plastic one bends when the filament is wrapped around it due to the tension in the filament.

Materials required

Alligator Clips Photo

Alligator clips

To connect to the heating wire and the cable connecting the battery

Insulation Tape and Medical Tape photo

Insulation Tape and Medical Tape

Insulation tape to insulate the steel rod of the handle from the heating coil’s wire.

I used the medical tape before applying the insulation tape because the wire gets too hot and get stuck onto the frame. So, to prevent getting scolded from my mom, I used insulation on the medical tape.

Heating Coil Photo

Heating Coil

The heating filament of an old fish tank heater.

The following is the list of items I used:

  1. Two wires with alligator clip at both ends
  2. Electrical insulation tape
  3. Wire cutter
  4. filament of an old heater
  5. Battery eliminator, I used a cheap 4 dollar battery eliminator (~12 volts)
  6. Pliers

For Safety

  1. Eye protection
  2. Insulation glove

A lithium-ion battery works too. I used a battery eliminator because it provides constant power and keeps the wire hot.
The heating coil element works best, I haven’t tried other elements, but I will if I run out of the coil 😉
(Edit: I tried it with a Nichrome wire and that works too…)
You could just solder the coil to the frame and draw wires from that but I used alligator clips because it was less messy and easy to replace if the wire broke.

Making the Hot Wire Cutter frame

Stripes of tape photo

Strips of tapes cut beforehand to make it easy to apply during the build

I had to cut the insulation from the middle too to make it easy to apply to the handle rod.

Apply tape to the frame
Almost done,
Apply tape to the frame
Add the insulation
Apply tape to the rod
Wind the wire over the insulation and secure it by winding it over itself
Wire winded over frame and itself
Finally, attach the alligator clips to the wire
Attach the alligator clips

Adding the wires

I used three wires in total here. Two for connecting with the 12volt power supply and third to provide support to the cable as a whole.But that’s not really necessary, you could just use two wires to heat the wire coil.
power cables
Attach the wires to the alligator clips

connect wires to the alligator clips

connect wires to the alligator clips

Thats it :)

Hot wire foam cutter Image

The Result: Hot wire foam cutter

For now, this is my go-to tool whenever I need to work with foam crafts. I have plans to improve the design a bit, making the cutter bigger to provide more cutting area :) .

Thanks for taking your time to see this tutorial. If you have any doubts please let me know in the comments.

Happy making!!! :)

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