Trumpet mouthpiece

thingiverse

My son demanded a plastic mouthpiece and we are currently testing this one with various internal shapes to determine how they sound. So far, he loves this shape the most and it's loosely based on the Olds 3 mouthpiece, featuring a shallow cup and slightly narrower design. I use food-safe PETG and carefully sand the rim while spinning it in a drill to achieve maximum smoothness. This is far from ideal, but it produces a working mouthpiece once you're done, hopefully it serves your needs.