I painted the tubes a contrasting color and let it dry. I lined a dowel with wax paper and used tape to secure the starting end of the ribbon to the dowel. The painted tube fits onto the dowel over the wax paper which prevents accidentally gluing the dowel into the tube. On the other end I tied a weight to the ribbon to keep things taught. Then coated the tube with 5 min epoxy, on the thick side, and then carefully twisted the dowel to wind on the ribbon. I went all the way past the other end of the tube and clamped the dowel in my vice to set up.
I made end caps by drilling a hole the same size as the tube all the way through, and the re-drilled half way though with a larger bit to accommodate the ribbon.
About a centimeter or so from the end of the tube, I scored the ribbon the whole way around with a utility knife, and removed that bit off the end. I used my wife's best snips to trim any stray fibers (this is the most dangerous part of the whole operation because my wife will know if I dull her snips!). After that it's just a dry fit, look, and trim until the end cap sits right.
