3.3. Assembly
To build Dirod #7, follow the directions for Dirod #6 up to the section entitled "Assembling the Corona Shield." The only design difference between Dirod #6 and #7 is in the additional fittings used to reduce corona losses in the inductors and collectors. Assemble two sets of inductors and lower collectors as shown below:
When you are confident that they have been assembled correctly, apply a little Goop or epoxy to each fitting, and then reassemble the inductors and lower collectors. Use only enough glue to hold the parts together will allowing the bare metal of the copper tubing to contact bare metal inside the fittings. If necessary, smooth the edges of the tubing so that they fit the fittings. Unlike the rods, however, the ends of the tubing are always inside fittings and so it is not necessary that they be smooth and round.
Each of the upper collectors is assembled from a tee (s), a tube (w), and a 45 degree elbow (u). The tee passes through a large hole in the corona shield. The collector brush passes through the small hole in the corona shield and is taped to the upper collector (w) with electrical or cellophane tape, just as it is in Dirod #6. The lower collector is then attached to the bottom of the tee, where it hangs down below the rods. With the corona shield in place, the disk should turn freely, the rods passing between the upper and lower collectors, and each rod should touch the collector brush as it passes.
The inductor can now be inserted into the collector's 45 degree elbow (u). The inductor should sit directly over the neutral brush.
When both collectors and inductors have been assembled as shown, the corona shield can be Gooped to the leg sockets and the copper fittings can be tacked to the corona shield with spots of Goop. Slowly turning the disk by hand, confirm that each rod contacts a neutral brush as it passes beneath the inductor and a collector brush as it passes between the upper and lower collectors. When you are satisfied that this is so, allow the Goop to dry overnight.
Just as with Dirod #6. A 1 inch length of tubing (z) and an endcap (x) are used to plug the top of the collector tee when accessories are not in use. They should not be glued, as they will need to be easily removed. You may wish to file the ends of the tube (z) so that it slides easily in and out of the tee.
Loop the belt over the pulley and spin the disk slowly clockwise. You should hear the crackle of static electricity. The small gap has not been included with Dirod #7 as you will certainly want to build a Rod Gap or a Ball Gap. With a pair of Rubbermaid Capacitors, #7 will give strong discharges the full 6 inches from collector to collector. A 2 inch ball gap gives discharges well over 2 inches across. Be sure to disconnect your belt when it is not in use so that it does not get kinked.