I wanted to make a long horn, which involved bending itself up and down a few times to make it more compact and playable. The areas where the pipe doubles back upon itself use an interesting solution for making the necessary bends. There is undoubtedly more turbulence in the bends of this instrument than there is in the smooth bends of professional instruments. It only costs a couple dollars to make, though, and it is so much fun to play that I'm willing to cut it a little slack in my critique.
The use of rubber bands in combination with clothespins is also an interesting technique for holding the rolled up plastic while gluing it all together with silicone rubber. They make adjustable, elastic clamps. They would undoubtedly come in handy for other projects, and maybe deserve an instructable of their own -- simple but effective holding devices.
Silicone rubber makes an excellent glue for this material. I use hypodermic syringes with plastic tips for precise application of the silicone.
Be sure to hear the audio sample of the jumbo sax tootophone in the last step.
Step 1: Cleaning the x-ray film
You can save yourself a lot of work by just letting them soak in water for a few weeks until the emulsion lets go of the plastic. You can then wipe it off with a sponge, and the plastic is free from scratches.
Wear rubber gloves to protect your hands from whatever chemicals may be in the emulsion. I saved the wash water, in hopes of someday reclaiming the silver in it, but have gotten nowhere with that idea yet.