I found a heavy duty sewing needle about the same diameter as the opening in the tube. I pushed the needle through the open core of the tube. Build up the needle on what is the front end of the tube with some tape.
The tape jams into the tube at one end, securing it and keeping it from rotating. The pointed end of the needle just gets inserted into the fly vise and locked in like a hook. If you luck out, you may not even need tape to hold a plastic tube in place.
Very cheap and efficient way of tying tube flies, if you want to experiment a bit.
All sorts of useful metal tubes of different weights can be found at a hobby shop.
Wes Wada Bend, Oregon
