Have you ever tried to cut styrofoam with a saw? Well I'll save you the hassle and tell you it makes a huge mess and a unclean cut. I was considering buying a hot wire cutter already made for ~$30, and then I realized how simple it is to make one. All you really need is Nichrome wire and a power supply, but having the PVC handle makes it so much easier and you get a straighter cut. For me the total cost was ~$10 as I had some pvc and other parts laying around, but it could be made for ~$20 if you had to buy all the parts. Another benefit of doing it with the PVC is that you can make it however long you want to allow you to cut bigger pieces.

Supplies

-2 pieces of PVC of equal length for arms (Mine were about 8in)

-1 piece of PVC for middle section (mine was about 16in)

-1 Power supply (could get away with 5v 2.5A, but 12v 4A cuts faster)

-1 Nichrome Wire (I used about a 1ft length between the sides after the space lost by the springs and screws)

-2 PVC elbows

-2 PVC straight connectors

-2 Small Springs

-2 Screws (with heads wide enough to hold the springs)

Tools

-(Optional) (Drill and bit slightly smaller than screw to predrill hole if desired)

-Side cutters of scissors to cut wire

-Screw Driver

Step 1: Attach Springs

For the first step you will need:

2 PVC straight connectors

2 Small springs

2 Screws with large heads

I first drilled two holes in the connectors slightly smaller than the screws, well actually I drilled the holes to big, then switched to larger screws, make sure to check the size first! Next put the loop on the spring on the screw and screw it in. (You can put the springs on after screwing it in but you have to bend the spring open and closed) Another tip is to not screw the screws in all the way so that the spring move freely, this will allow the springs to hang straight down and put less stress on them.

Step 2: Assemble the Frame

A pretty easy step, just push fit the PVC together as shown. You could glue it, but I dont really think its necessary if you push them together firmly.

Step 3: Add the Wire

This is probably the most important step. First you need to choose the nichrome wire to use. They are usually measured in ohms per foot, the one I got was 2.57Ohms/Ft. Using ohms law you can calculate the current draw using the voltage and resistance (Make sure you use a power supply rated to handle the current at the desired voltage.)

Wire I used: https://smile.amazon.com/gp/product/B07CHVKKCQ/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Ohms Law calculator: https://ohmslawcalculator.com/ohms-law-calculator

Also note that as you increase or decrease the length of the cutting wire, the resistance will change (I just used a length of 1ft to make it easy)

Once you have your wire, connect it to the springs at either end, these will help to keep the wire tensioned and your cut straight.

Step 4: Connect Your Power Supply

Next, attach the power supply wires to either end, I used alligator clips as the wire will permanently stretch during the first heating so you will need to let it cool, then re-attach it to make it tighter. These clips also make it easier to switch power supply's if desired.

Step 5: Turn It On!

That's it, plug it in and start cutting! (Be Careful, it is very hot!) It is pretty fun to cut with this thing and it goes through foam like a hot knife through butter, I spent about 10 minutes just cutting a big foam piece I had. Enjoy!

Please post any questions you have in the comments and I will answer them as fast as I can.