air variable capacitor from scrap aluminum sheets

Step 17: Plastic jar caps

Cut two triangular shaped plastic from jar caps. Or any plastic of your choice. This plastic will insulate the rotor contact from the aluminum housing. I just glued my contact temporarily. I will later change it with a copper connector. The ones that look like washers like the ones used for ground connection.
Now you just put the two triangular plastic on both sides. Followed by the two triangular shaped aluminum and you are done.
Remember if you have two stator plates, you must have three rotor plates. 4/5, 5/6 and so on.
I hope that this instructable will be of much help. Thanks :-)