Getting the form Right
Raw FRP shell condenser shell form
Condenser shell form
I April 2012
The raw FRP ( Fiberglass Reinforced Polyester) shell form needs to be repaired and trued before the actual condenser can be created on it. Due to working alone there are starved areas in the FRP where there is not enough polyester resin to float the fiberglass. These white streaks are weak areas and need to be ground out and refilled with FRP before the shell can be built up and trued. There are many high areas that must be ground down to a minimum thickness and all other areas built up to obtain a smooth and true curve with little or no ripple under the capacitance foils.
After the minimum thickness is true and strong and stable, the low areas that remain can be filled with resin fillers and further trued. It took most of 6 weeks to get to this point. Now the edge must be trued to the center point so the curvatures are even and smooth.
Electron fields concentrate at points of sharpest curvature and we want the fields to maximize at the disk edge with the least loss. The more true and smooth this surface is the better the quality of the capacitance layers to be created on it. Any high areas can result in thin dielectric and possible failure. Any low areas will result in loss in capacitance.
marking the shell form for truing
To obtain a true edge a wire is connected to the top center point and used to draw concentric circles that are tested with the template that is a cut and marked piece of heavy corrugated card board. The use of this shows the areas that need to be ground down or built up to achieve a true shape. After nearly 3 gallons of filler the surface is very true. Now layers of polyester resin are applied and sanded to create a smooth surface, each more smooth and true then the last. Now I need to clean the work area as everything is covered with a thick layer of polyester dust. 😥
Now to add the coils
The great coil and plasma jet in place
The 130 turn spiral wound high voltage coil has been cut out of the old device and mounted under the disk frame with the plasma jet pointed down.
The black coil around the spiral coil is the 24 turn primary coil, and the white coil above it is the bundle of driver coils for the twitch coils.
Inside of the central frame cage is the shell field driver coil that is connected to the groundplain in the rim and to the surface field cap on top of the coil and the outer skin of the shell.
Center coils inside disk
The shell field coil is induction driven 165 turns of 12ga tw covered wire and should create a 100,000 volt field on the shell capacitance due to the 600+ volt per turn field strength.
The shell field coil and twitch coils are loosely coupled to the main field and are jointly connected to the groundplain to make their operation independent of any back EMF from the spiral coil and primary driver that are connected together as an autocoil.
The primary and spiral coils should drive the plasma jet pincushion to about 100,000 volts. At some time the primary coil can also be connected to the groundplain if needed for testing.
Twitch coils in place in disk edge
The primary coil is a bundle of 24 turns of stranded 12ga THWH inside polyethylene tubing and is powered by the 15,000 volt spark gap set. This should set up a 600+volt per turn field inside of all the coils
The twitch coils are mounted and connected to the groundplain. 2 turns per twitch coil are bundled into the white twitch coil driver necklace above the primary coil to independently provide 1200 volts to each twitch coil LC set. The twitch coils are 90 degrees to the other coils so are nearly independent of the main field.
FRP shell with cap in place
Every other segment is connected to the groundplain and bottom of the shell field coil. A coil/shell cap with carbon fiber whip has been created and covered with aluminum foil to act as the connection from the top of the field coil to the shells’ upper aluminum covering. The upper third needs to be trued by grinding and filling to the finished level as I prepare to apply the inter condenser copper foil.
Construction of the Actual Shell Condenser
Inter Layer of copper foil
The FRP shell is ready for the addition of the copper foil segments that act as the inter layer of the shell condenser. Each segment connects to one side of the twitch coil behind it
Next, add the shell condenser copper foil inter layer on the shell form. After several attempts I have found a way to apply a satisfactory copper foil layer to the form.
WOW! This is starting to look impressive! If nothing else this is a work of Art or at least of PG. 😎 When the outer shell is finished this will be stunning! even if it doesn’t move.
The blue level is tape to hold the foil segments against the wires from the interior circuits. This is removed as I create the outer edge.
The outer edge form is done .
Fiberglass gores in place on shell
The outer edge shape is done and I am ready to build up the FRP shell over the inter condenser foil level. The Resin needed is on hand and the fiberglass mat is on its’ way. Hurrah! the end is in sight.
The Fiberglass mat has arrived and is being applied. Gores of mat are cut and taped in place with a slight overlap, then catalyst treated resin is poured on and rolled into the mat until the glass “floats” and air bubbles are eliminated. Fast work is necessary to complete the fill all the way around before the resin sets. To successfully make this, by myself, it is done in 3 layers. Each layer of mat requires the application of 3 and a half gallons of treated resin.
finished shell with aluminum skin
The shell shape is complete and covered with aluminum foil gilding.
A few coats of polyester and sand it smooth.
I just, have to, smoke test this!! Chase a few electrons around and around! light up some old florescent tubes.
It has been nearly 20 years since I energized the great coil
27 February 2013
Polyester coated Shell condenser outside the hanger area.
The polyester coated shell is well cured and has been moved outside the hanger area. Now I have a lot more room to work and I have the greenhouse back 😎 for early spring grow out.
NOTE: Be sure to click on the pictures for a better view and more information in comments. pg
Next see Condenser Disk and Hurrah!