an old coil page from my first web page

My coil specs

secondary........form 2.75"X15" acrylic tube 1/8"wall (clear)

coated with acrylic resin spray

end caps cut on milling machine from 1/4 sheet acrylic

wound with approx. 800 turns 28awg magnet wire salvaged from a relay coil and from a refrigerator evap. fan motor

heavy coating of acrylic resin on windings to fix them in place and to act as insulation

the secondary is supported on a 5 3/8" dia. Plexiglas disk with screws to allow for height adjustment

primary.......7 3/4 turns 5/16 copper refrigeration tubing on a Plexiglas disk

tubing is supported in grooves milled into five polyethylene strips 1/2 X 1 X 5 3/4"

cut from a plastic cutting board like you get from the grocery store

the pri. coil form will take nine turns but the copper tubing I had laying around only was long enough for 7 3/4

the inside diameter of the primary is 7 inches. it is a plat pancake design

RF ground is to a water pipe going into a slab with a lot of steel and steel posts into the ground all tied together

from this ground to mains ground reads less than 0.5 ohm

connection from the ground strap coming out of the base of the sec. to the water pipe is heavy welding cable

toroid (the one I use) is 4" dryer duct 13 1/2" OD

capacitor is saltwater...4 Budweiser longneck bottles in a bucket

wine bottle stoppers (cork) and 1/8" brazing rod for connections

measures .oo345uF (a little small)

high voltage transformer is a 9kv 20ma Franceformer NST

Spark gap is a single adjustable static gap with air blast quenching

no protection circuitry is employed

max spark length to date (white hot continuous arcs to a grounded brass float ball)

9" at 160volt setting on the variac

normal spark length is about seven inches with 125 volt going in (NST not overdriven)

of course the wispy weak sparks will reach a little farther but I don't count that

Next on the list to do is to make a real capacitor. My present project is modifying a microwave oven

transformer. I cut the welds with a grinder and took the core apart. Then I removed the secondary.

A new secondary is still on the winding jig. It is slow going because each layer is sprayed with polyurethane

and allowed to dry, wrapped in polyurethane saturated Kraft paper and allowed to dry. then another layer wound.

I am shooting for 7.5 to 8 KV. The current should be 125+ma continuous (no current limiting)

Also I picked up a 6 1/2" dia X 58" long fiberglass pipe. Lets see....I just happen to have a couple of pounds

of 26awg magnet wire sitting here....