Reel-to-Reel Audio Tape Becomes 3D Printer Filament

All FFF (fused-filament fabrication) 3D printers use thermoplastic filament, which means that it melts and then re-hardens without degrading when it cools. That should naturally lend itself to recycling, because discarded thermoplastic parts can be melted down into new filament. But in the real world, it isn’t quite that simple. There are many reasons why recycled filament isn’t common, including the inclusion of additives in thermoplastics. But some attempts result in success, as brtv-z demonstrated by turning old reel-to-reel magnetic audio tapes into usable 3D printer filament.

Reel-to-reel audio tapes work just like cassette tapes, they’re just larger and aren’t permanently encased in plastic enclosures. They became popular in the mid-20th century, but were almost entirely obsolete by the turn of the millennium. As such, old reel-to-reel tapes are worthless today (aside from the content they might contain). That tape was made from a variety of materials over the years, but forms of PET were common. As many 3D printing enthusiasts already know, PETG is a common filament material. PETG uses glycol to improve printing performance compared to regular PET, but the latter is still printable.

To turn old Soviet tape reels into filament, brtv-z built his own custom filament extruder. It takes a bundle of tapes, feeds them into a hot end, out of a nozzle of the proper size, and into a stepper motor-driven extruder that pulls the filament out. The resulting filament is very rough and makes even the worst factory filament look consistent. But it is PET thermoplastic in filament form, which means a 3D printer will at least try to work with it.

As brtv-z shows, this filament works. But the results aren’t exactly impressive. Because the material is so inconsistent and sticky, it produces parts that are somewhat porous. The parts almost look like they’re made of dark lava rock. You would never want to use this filament for a part that needs to be strong or dimensionally accurate, but it does have an aesthetic that looks kind of cool on decorative parts like vases. Recycling audio tapes for this process isn’t practical, but it is still interesting to see.