Making a Prop Sword From Cheap Foam Panels | Adventure Time

Need a cosplay sword or a display prop? We made a cartoon sword from the show Adventure Time out of cheap insulation foam and a hot wire cutter. This Demon Blood Sword is a silly way for me to try out hot wire foam cutting.

1. Gather Source Material
2. Cut Foam Panels
3. Coat and Paint

1. Gather Source Material

This project is an excuse for me to finally use a hot wire cutter to easy cut foam. I decided to make a sword from one of our favorite shows, Adventure Time. We really love the striking Demon Blood Sword, it is red and vibrant and cool looking. To get some real-world measurements, I found some images from the show and did some proportion math to scale it up. This is a very common practice when making props, you find the best images you can from the show or movie, measure it on the screen and translate those measurements to full-size materials.

2. Cut Foam Panels

Now that I have the sword’s dimensions, I can laminate the material, foam insulation panels. These panels are readily available at most home centers and come in various thicknesses. I used some Super 77 spray adhesive to glue the panels together into a large rectangular blank. I made sure to insert a wooden dowel down the middle of the blank to give the sword some added rigidity. Next, I transferred the full-scale dimensions to the blank using a ruler and a compass. Now comes the fun part, the hot wire cutter.

A hot wire cutter uses an electrical current to heat a thin wire that can melt its way through most foams. This tool leaves a very smooth surface on the cut parts in contrast to most blades or knives. The cutter has different attachments to make different cuts, which is great because this sword has some tricky geometry.

3. Coat and Paint

Once the sword was cut and sanded, I could add a coat of epoxy to the surfaces to make it stronger. In the video, I experimented with adding fiber glass strips to the blade for added strength, but it didn’t work super well. The coat of epoxy smoothed out the surface and added the strength I was looking for. Next, I covered the sword in some glossy red paint and did some cell shading painting to highlight the cartooniness of the prop. Lastly, I sanded down a block of wood for the handle’s tooth, and the Demon Blood Sword from Adventure Time was done.

I Love Learning New Skills

While I really love Adventure Time and I think my Demon Blood Sword is super cool, I’m really happy that I got a chance to use the hot wire cutter. I love making props out of foam and this tool can make that process so much easier. I was really impressed with how simple it was to use and how clean the cuts were. There is a link in the side bar if you want to get one for yourself, they aren’t very expensive. I hope this project gave you some inspiration to make something from a cartoon in real life. Whether it is a silly sword, a cool helmet, or a suit of armor, foam is good for them all.