DIY Cheap Hot Wire Cutter




About: I love making tutorials on my hobby projects :)

In this instructable i will be explaining the process of making a cheap hot wire cutter, which can be used to cut through Polystyrene, foam.

This Hot wire cutter runs on 12 volt DC, I use a Battery eliminator circuit to provide constant power.

The filament is from a cheap fish tank water heater coil (straightened out, you could use a heater's filament, but I haven't tried that yet), the holder is an oven's tray handle thingy, and I reused an long wire from a previous project, you could use a two long independent parallel wires, but I used it with a third wire for added strength.

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Step 1: Type of Frame

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

Hacksaw, It can be done, but the frame was a bit heavy for me

Cloth hanger, it is probably better but the frame was a bit weak, it needed a little reinforcing.

You can use pretty much anything Y shaped.

Step 2: Tools and Stuff

1) Two wires with alligator clips at both ends,

2) Electrical insulation tape,

3) Wire cutter,

4) filament of an old heater,

5) Battery eliminator, I use a cheap 4 dollar battery eliminator,

6) Pliers,

For Safety

1) Eye protection,

2) Insulation gloves

Sorry for the messy background, but if anything was unclear please ask in the comments.

You don't have to use a battery eliminator, you can use a battery. I used it 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 ;)

You could just solder the coil to the frame and draw wires from that but I used clips because it was less messy and easy to replace if the wire broke.

Step 3: Build (Part 1)

You could simply use the electrical tape but in my case I could't stain the handle so I used a non sticky tape as a base and wrapped the electrical tape around it.

Keep in mind the wire should be under tension but not too much, or it will snap because I am using a very thin wire to be able to run on 12 Volts.

The wire must not touch the metal frame, make sure the winding's are well insulated from the frame.

Step 4: Wiring (Part 2)

The wiring from the cutter to the battery eliminator are just two parallel wires, the third wire is for added strength.

Step 5: Safety

Wear eye protection and safety gloves at ALL TIMES when using the cutter. Eyes are your best assets, protect them.

Step 6: Use

These were for a scratch built rc plane.

The filament cut through like a knife through butter :) but it was bent a little in the middle and the result was a wavy finish, but cut pretty smoothly.

If you have any doubts please feel free to ask in the comments,

Thank you for your time :)



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    4 Discussions


    3 years ago

    hI I TRIED making it by cutting a length from 1000watt heater coil, with 9v DC but didn't work. i have 3 4v lead-acid battery, can i achieve it using them ?

    1 reply

    Reply 3 years ago

    I wouldn't recommend that, but what you can do is use a 12volt DC supply with the wire. Also, you should just buy a nichrome wire as it is very durable and lasts longer.


    4 years ago on Introduction

    If you want a really thin but very, very strong wire. Try using Nichrome. I buy fishing leader wire and simply cut off what length I need. I purchased a complete roll but since making my cutter over 5 years ago I haven't had to change or replace the original. The wire is used by fishermen as what's known as leaders. The wire which goes from the end of the nylon to a swivel just before the hook. It has to be tough because that's where any line suffers from abrasion and teeth bites from the fish.

    Try it, you'll never use anything else. You can also find Nichrome in heating elements, (heaters, toasters) much better if it's never been used, as these items tend to be run at much higher temperatures which over time can lead to the wire breaking down and going open circuit.

    1 reply

    Reply 4 years ago

    yeah I'll try nicrome, the wire I use breaks off very easily, but it was worth a shot