I saved somebody else description on how to make one some time ago.... Here you go

You can build one for under $20.00.
1/4" piano wire.
brass tube to fit the piano wire.
small spinner about 1 1/4"
Allen L shape tool that fits your spinner nut ( get from Sears or a good hardware store they come as single ).
Two nuts and washers to fit wire.
These are all the parts that will need to put it together. I forgot my wand once so I run to the hobbie shoppe and made me one in 1/2 hour, instead of using a plastic spinner I used a shaft counterbalance the one you put on the engine shaft it will fit the 1/4" piano wire tight, no need of welding or anything.

Choose your length once you have it ( about 20" long ) cut the wire.
Cut the Allen tool at the turn and clean it at that end 'till it shines to get a better grip ( Dremel tool works well ).
Do the same to the wire.
Now cut a piece of brass tube to fit over the wire and the Allen tool ( about 4" long ).
Solder the Allen tool, wire, brass tube make sure this is very strong and that there is no gap between the wire and the tool ( use a small torch ).
Now you should have a wand with no starting cone.
You need to secure the cone, you can do this by ( welding, threading this end of the wire ).
OK, next clean the wire and add some kind of lubricant.
Cut and slide the brass tube to fit the wand , leave enough room for the spinner, you should have about 1" of room for the brass tube to move up and down the wire once it is completed.
You can use two nuts and washers to secure the spinner, one outside, one inside.
At the time of usage the brass tube will rest on the outer nut.