I am using parallel discs for this one.    As soon as I finish stuffing the tube and wiring it up, I will calculate and then measure the capacitance.  Except for the nuts, bolts, and galvanized washers, all materials in these capacitors have been rescued from heading to a landfill. There is something gratifying in that.

Check out the laser action too!  I still think that is like magic.   Prior to cutting plastic parts, I cut diameter samples out of cardboard in order to check for fit inside the pvc pipe.  Using cardboard or paper prior to running “good” material is a cost and time saver (thank you, John Duane!).

Here is a video of the laser re-cutting the discs as the material was a bit too thick for the speed which the head was traveling at.  When you see sparking, that is the laser beam striking the Aluminum honeycomb bed below the plastic.[quicktime]http://www.terezakis.org/itp/video/40mm-laser-4-9837.mp4[/quicktime]

Assembly went well. The washers and laser cut discs were a great fit. When I get time I will measure and test.