3D-printed ‘balloon banjo’ is ready for pickin’

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The banjo is an infamously difficult to learn musical instrument. Mastering multiple open tunings makes the learning curve much steeper than the guitar, while its many complex finger picking and roll patterns only add to the challenges. But if you are looking for a much simpler alternative to the bluegrass staple, the designers at Co:Creation Lab have you covered. All you need is a 3D printer, some nylon fishing line, and an everyday party favor to build a diminutive “balloon banjo.” But as the team’s short demonstration video shows, it’s immediately clear that their ingenious instrument is much more suited as a children’s toy than something to show off at the next pickin’ party.

Balloon Banjo — a 3D-printed instrument whose sound box is a party balloon

The balloon banjo is less of a feasible music-maker and more of a  homebrew science toy project for parents and kids, but it’s still a cool and relatively straightforward concept. After downloading the design files, builders 3D-print only 19 pieces that then snap together to form seven separate parts. These are then secured using 3D-printed screws that can be turned by hand. The assembled frame houses a basic rubber balloon that serves as the sounding board, while nylon string or fishing line functions as the instrument’s strings. Adjusting the amount of air in the balloon alters the overall resonance—but that’s about it as far as tuning goes.

The small invention is more suited to demonstrate engineering and acoustic principles than playing “Camptown Races,” but it’s still a cool afternoon DIY project if you’ve got the time and materials. As Hackaday notes, both the strings and balloon will inevitably require replacing at some point, but both of those are much cheaper than the average banjo.Or even the inventions found at the annual Guthman Musical Instrument Competition.