This is a printable trombone bell, I modeled after my bach trombone bell. It plays fairly well. Here are pictures: http://imgur.com/a/0WV4N Here is a video of me playing it: https://www.youtube.com/watch?v=LAZR8elS6lg Created by Logan AusenMake the test.stl first to see if it fits with your existing slide. So far the test only fits on bach slides so I will edit that as soon a possible. When printing piece tb1.stl check if it is a making a round or rectangular connector. Round use con3.stl. Rectangle use con2.stl. Watch the build for the tunesl.stl to make sure it does not mess up. It messed up once for me. Try to follow the diagram and a glue the pieces together. http://imgur.com/a/vZsp7 Then fill in any leaks or holes with glue. I glued the holes first then sprayed it with a rubber plastic. Hope the build works well. Comment below for any further questions.