I really wanted a cool tube full of neon-colored liquid on this project somewhere. So, I scoured the internet and found a good deal on 2.25" Diameter, clear polycarbonate tubing. (Wound up with 8' of the stuff.) And then found 2.25" diameter Rod to go with it.
The tube became the body and the rod was cut and then machined on the lathe to fit within it with G1/4 threads.