I have a project where I will take a small tube (say, 11mm in diameter and .5mm thickness) and cut a 9mm band from the end.
Then I will cut a section of that band to make a clip:

I need that clip to be flexible enough to 'clip' onto a rod that is 12mm in diameter (and tapers up to 18mm) yet is firm enough to hold itself in place.
I have been testing carbon fiber, but it just won't budge (literally) when it comes to initially 'clipping' onto the rod. It snaps every time. Other more flexible sources that do clip on end up being stretched and won't hold tight.
Any ideas?