$5 DIY Hot Wire Foam Cutter




About: So basically i am a crazy person, who loves to think the most odd way ever possible,who makes what he thinks and also let other also make those . Check out my crazy projects if you like do follow me :D

Hey Guys, It has been a long time I have not written an instructable.
In this instructable, I will show you how to make a StyroFoam Cutter using things that are lying in your home.

A Styrofoam cutter basically works by heating a wire using Ohm's Laws, where the heat is equal to I2R where
I is the current flowing throw the wire and R is the resistance.
Now Nichrome has a resistivity ranging from 1.10 × 10−6 Ωm to 1.50 × 10−6 Ωm.and a very high boiling point (~1400 °C).

btw guys if you like this Instructables please make sure you hit the vote button, to let me win for the plastic contest.


Step 1: Cut the PVC Pipe

We first start by cutting a PVC pipe, I had a 2 feet foot long one so I needed to cut into the following length

  • 12 " long
  • 4 " Long

Step 2: The Connectors

Now for this whole build, I had used three PVC connector.

  • 90 degree Corner
  • PVC end Cap
  • PVC Table Screw

The Corner was painted, Black by a Spray Paint

The PVC Table Screwand End Cap was actually 3D printed as I was not getting in the local market so I designed my own in Fusion 360.

You can learn a lot from Instructables Classes about Designing in their class.

Step 3: Fix the Connector

Now it was time to fix the table mount connector to the melamine board. So I drilled some holes using a 3 mm Drill bit.
I used my Black and Decker Drill Cordless drill for that. Then using 3 1/4 inch Screw I have attached the mount to the melamine

Step 4: Assemble the Pipes

Now it was time to assemble them. I first fixe the 12 " pipe and 4" pipe using the corner Connector.
Then I connected one end of the 12 " pipe to the table mount. The other end of 4 " Pipe will be connected to end cap.

Step 5: Preparing the End Cap

Now it was time to prepare the end cap, the end cap will be holding the spring which will stretch the nichrome wire. Now since an end cap doesn't have a hole, I didn't design that rather took my drill to make a hole. I mounted an eye hook then to end cap and fixed it with a nut .

Step 6: Adding the Ni-chrome Wire

Now it was time to add the main thing, the NiChrome wire.I had got this Nichrome wire by salvaging it from Hair drier. The Wire was then mounted with a spring to the eye hook. The wire was stretched to keep the tension on the wire so that it won't get deformed while cutting.

Step 7: Preparing the Wires

Now it was time to add power to wire so that it can cut like butter. I used a 12V 5 A Adapter to Juice the system, to connect the system all I did was to solder the wire to the Crocodile clip and then attach the crocodile clip to the wire when needed to be used.
One more advantage of the system is that by changing the position of the clips the resistance change and hence the current, so the max temperature also changes. This helps when dealing with thin foam sheet.

Step 8: Adding Rubber Feet

Lastly, I added some rubber feet so that this won't scratch the table when used on it. you can skip this step, if you want but this makes the station more usable on the table and also it won't slide here and there when used to cut foam.

Step 9: Enjoy Foam Cutting

So what is the material it can cut ??
The foam cutter can cut

  1. 2-inch Foam sheet
  2. 10 " Depron
  3. Foam sheet
  4. Foam Block

BTW guys if you like this project and want to get updates on what's cooking in the workshop follow us on Facebook. https://www.facebook.com/makewithrex

and Subscribe us on Youtube https://www.youtube.com/prajjwalnag



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16 Discussions


Not sure if you've been informed, but the "Download" link doesn't really work (maybe it's just me) - I get one stretched-out version of the first page only. I guess it could be an Instructables issue ?


6 months ago

Please show what happens under the board


Question 6 months ago on Introduction

What is your power source? From the hair dryer? Any safety issues addressed in doing so?

1 answer

Answer 6 months ago

He clearly stated a 12 V 5 amp supply. You could use something like a notebook power supply or probably the best bet is a variable voltage bench power supply. We bought one that goes up to 30 V and 10 amp for about $70 to anodize aluminum. You can get 5 amp supplies for a lot less. Using 120V would be dangerous since if you got across the two ends of the wire, you would be hooked to 120 V.


Reply 6 months ago

Foam board as in Foamcore? I would say you could cause a fire, and the wire might break. I have never seen anyone try and cut Foamcore or Gatorboard, but a sheet of EPS Styrofoam, yes, quite easily.


Answer 6 months ago

Good question. In the film industry, us professional sculptors (Sculptor's Union Local 755) we use a Variac Voltage Control Machine. They are very expensive, but worth the price, because you can control voltage from very, very, low to very, very, high. Here is a link to a site that carries these machines.



Answer 6 months ago

It was written in step 7
It is Powered By a 12V 5A Adapter


Reply 6 months ago

Thanks. I was looking for it but somehow missed it.


6 months ago

Very nice build. I want to chime in as I had been a sculptor who has worked on some really huge Hollywood feature film productions sculpting massive sculptures for feature films as well as sculpting huge movie sets like rockwork for movies such as Pirates of the Caribbean for Disney and Planet of the Apes (Tim Burton's film) and many other films and television shows.

What I wanted to say to anyone working with Styrofoam (a.k.a. EPS foam) especially if you are using hot wire or hot tools, even heat guns, to cut and shape it, you absolutely MUST wear the highest quality respirator with extra charcoal filters, otherwise, you could end up like me, and find out that your body has an excessive, even massive amount of Styrene in your blood and fatty tissues. I actually did wear fairly high quality respirators when working with this type of chemical foam. And yet, this chemical is highly pervasive and apparently finds other ways to enter the body besides the lungs. Always suit up and wear a disposable protective suit and cover your head/hair and wear disposable gloves when working with Styrofoam (EPS foam).

Keep in mind that all of these foams in their many forms are all made from the processing of the base source which is from crude oil. Crude oil is a highly toxic substance that can be and is refined into literally thousands of other highly toxic, cancer-causing chemicals which are very poisonous. Take EVERY precaution when working with what we have all been led to believe are just wonderful, simple-to-use, everyday materials that make our lives easier and more enjoyable.

If you are only doing two or three projects with this foam, then it's probably not a problem, but if you work with it every day as I did, then take every precaution. Have fun DIYing!


6 months ago

Do NOT heat cut foam in a closed environment. Make sure ventillation is very high.


6 months ago

Nice construction, the spring is a great idea. I assume you mean MELTING POINT not BOILING...


6 months ago

Simple, clever construction. Thanks!