Rough edit for how to make your own howwire cutter to turn EPS foam packaging into walkalong gliders.
I slice foam for Spinny Gliders about 2mm thick, but I use low-density foam. Packaging foam is usually denser, so it’s stronger and heavier, so I suggest you start with about 1 1/2 millimeter thickness. The dimensions for the Spinny parts are 40mm x 125mm for the rectangles and the circles are 40mm diameter. The EPS foam is 2mm thick but it is low density. For common EPS density, 1.5mm might be best. The foam thickness for small fixed-wing gliders is about 0.8mm, but again it could be thinner if you are using denser foam. Big gliders can benefit from being thicker, for stiffness, but at some point it becomes so thick that it cracks when you try to bend it (the thick Spinny glider has no folds). You can mitigate the cracking somewhat by crushing the line where the fold will be with a ruler or something.
The most common density for EPS foam in North America is one pound per cubic foot density, which is about 16 kilograms per cubic meter. I mostly use foam that is only about 75% as heavy as that density, the lowest density foam in North America and Europe. Some foam made in China goes as low as 5 kg/m ³, which is only a few times heavier than air itself (about 1.25 kg/m ³, depending on altitude/temperature/pressure/humidity). There’s a video just about the ultra-low density foam, https://youtu.be/b54h2-_OHJc?si=j-OHVKxRidYOyZNB
Here are some ideas for finding foam.
* Put the word out to your friends to be on the lookout for packaging from electronics. * Appliance stores that sell, stoves, refrigerators, TVs, etc. are likely to be throwing away foam. * Back in the day I started with foam containers that fresh seafood is shipped in. It’s dense with no holes. It smells like the ocean when you cut it. Just be sure that it’s completely dried out before cutting; a little drop of water will stop hotwire cutting instantly. * You might encounter a particular kind of packaging EPS, from China, that’s extremely low-density—only a few times denser than air itself—that I call “Time Warp” foam. I have a separate video all about that, linked below.