Spyder,
Get 4" PVC pipe (length you need) at Home Depot, etc.
Get a 4" PVC cap for one end of the pipe.
Get a 4" Female Threaded Coupling for the other end of the pipe
Get a 4" Threaded 'insert' (threaded clean-out cap) to screw into the coupling.
Get 1 small can of PVC glue.
Glue the cap and female threaded coupling on the ends of the pipe. The threaded insert is removed by hand when you want to put your stand in (or take your stand out) of the tube. Also, if you plan on attaching a strap, it would be easier to attach the strap before you glue the cap and coupling on the ends (If you are using short bolts to hold the strap on, you need to be able to reach inside from each end and install the lock-nuts onto the short bolts)