I 3D-printed a working trombone!
It's mostly based on the design from https://www.youtube.com/watch?v=OI0A-zdRvIk but the 3D printer I used is too small to print some of those parts, so I had to get a bit creative with cutting and gluing/taping.
In theory it should sound decent, but I'm pretty bad at playing the trombone. See the end of that video for a demo by someone who actually knows how to play the instrument.
I 3D-printed a full-sized tenor trombone! (Except for the metal mouthpiece and PEX slide)
It's mostly based on https://www.printables.com/model/324716-printbone-pex-slide-files and https://www.printables.com/model/80017-the-printbone-v11-a-fully-printable-playable-tromb with a few slight modifications, and cost around $35, most of which was for the mouthpiece and PEX tubing.
Technical details:
It's surprisingly usable as a musical instrument, the partials are all mostly in tune, and false tones and pedal tones are pretty easy to play on it. It has a 0.485 inch bore and 8.5 inch bell.
Unlike the alto I printed, the slide isn't squeaky and didn't need lubrication. Again, no water key so I have to empty the water by pulling out the whole slide.
WHOA this guy can throat sing while playing the trombone? https://www.youtube.com/watch?v=Gl3r22rz2rg
All my tricks look trivial in comparison
I have the opposite problem. In real life, a gig bag actually protects guitars better than a hard_shell case, but as soon as you get into somewhat nice guitars they include a hard_shell case, and you are stuck with a case too heavy to carry. And you have to buy a gig bag for it.
But condolences on your problem: trombones are more easily dented than guitars.
Thomas Brand
David, a Bostonian in Tokyo.