Leyden Jar of DOOM!




About: Electronics engineer with allot of mechanical design expertise email nickademusss@yahoo.com I dont check here often for messages so email me if you have one
OK so you have built a large
Van de Graaff Generator
now you want to take it a step further and up the spark current.

A good way to do that is to use a leyden jar and build up a large charge in it and watch the powerful sparks fly.

This Leyden jar is made from a 5 gallon bucket and stores enough electricity to kill you.

I strongly recommend building a smaller one unless you know what your doing.

The leyden jar is a very old design dating back to the late 1700's
Its simply put a high voltage high capacity capacitor.

Built properly and treated like a loaded gun you too can make your own miniature lightning bolts.
Trust me when i tell you that a discharge from this device is loud enough to damage your hearing so wear hearing protection.

I have experimented with high voltage for many years this is one of the more dangerous projects I have completed so please be careful. I accept no responsibility for your injury or death.

Have fun and please be safe,
Zachary M.

Next up parts list.

Step 1: Parts and Tools Needed


5 gallon plastic bucket
Roll of aluminum foil
copper pipe 1/2" diameter or larger
small piece of copper sheet
round door knob
spray glue (i used contact cement)

Drill with bits
masking tape

Step 2: Ready the Bucket

Remove the handle with the pliers and clean the bucket inside and out with alcohol.

Next you will want to make a perfectly level line around the bucket about 10" from the bottom.

I stacked some books next to the bucket and held a sharpie on them and turned the bucket around wile marking a perfectly level line.

Step 3: Tape It Up...and Spray

Tape along the line you just made.

now spray the out side of the bucket with a few coats of contact cement.

On a smaller leyden jar i would recommend aluminum duct tape, but you have a huge surface area to cover on this one.

let the glue dry...

Step 4: Put on the Metal

I started with the center of the bottom and pushed the metal into every crevice I could.

I also resprayed the bottom over the metal and put on another coat for a little more durability.

next do the side getting out all the wrinkles as you go along. If you used the thickest aluminum foil one coat is fine.

just coat up to the tape line. I let mine over lap and I cut along the tape with a sharp knife to make a perfect edge.

Step 5: Mark and Tape the Inside of the Bucket

Next I measured down the bucket to the top of the foil and made a mark on my ruler.

then I taped a piece of plastic to the ruler on that mark to make a makeshift gauge.

I then used it to mark the inside of the bucket. Simply but it up against the lip of the bucket and mark below the end of the ruler.

Step 6: Tape the Inside and Spray It

Tape off the inside and spray it as you did the outside.

Step 7: Foil the Inside

I started with the bottom and then glued strips up the sides.

I also cut off the excess and made sure the edge was sharp and level.

You can over lap the foil just spay the glue on the foil and let dry then apply.

Step 8: Center Post

I wanted a good connection with the center post so I cut the pipe so that it ends about eight inches above the rim of the bucket and soldered a piece of copper sheet 4" square on one end.

Step 9: Center Post Installed

set the center post in place and glue it down with strips of foil.

Make sure its as close to center as you can get it.

Step 10: Put on the Lid, Opperation

Now simply drill a hole in the center of the lid and put it on the bucket.

Secure the door knob to the tip of the post and its done.

I will be looking for a better ball for it and will post the changes later.

Now that you have built it simply connect the doorknob to a VDG and charge up!

For a big spark connect another door knob to a pole that is connected to the outside of the leyden jar.

It will be the negative side and the center post the positive.

To discharge it without hurting your self, make a set of discharge tongs from the old bucket handle and put them on the end of a fiberglass pole. Then short out the outside of the bucket to the center node. Yes a large spark will occur.Touch the outside of the bucket first so as to not burn holes in the aluminum.

I will add a video when I get my test stand done.

Thanks for looking and please be safe.
Zachary M.



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    149 Discussions


    1 year ago

    All that room in there... Im wondering to experiment with a coil in there to see if can perhaps pick up in a way to step down or achieve some other awesome effect that is not yet discovered.

    Otto Carr's antigrav was two plates like a capacitor, but they rotated in opposite directions initially. They then went to sending an alternating electric field into each plate, with the electric fields going in opposite directions. I presume like eddy currents... and static high voltages creates the dual field canceling out in the sweet spot. His interview said they lost one proto type to outer space... think it was in the 50s. Lots of stuff kept secret.



    3 years ago

    what liquid did you use inside, iv'e heard plain water works but iv'e also heard people use a 50/50 mix of baking soda and water, and a 50/50 mix of vinegar and water

    3 replies

    Reply 3 years ago

    There is no need for a conducting liquid in this case because the foil on the inside is right up against the inside wall. The liquid is normally only used as a work. The liquid fills the volume, effectivly bringing the conductor to the sides of the bottle.


    Reply 2 years ago

    In that case then couldn't you scale this down to be just as effective or is the surface area that important?


    Reply 2 years ago

    The surface area is one of three things that are important. The other two are materials and distance between the foil. Capacitance will go up as surface area goes up and the distance between the foil goes down. If you are mathematically inclined, the equations for a parallel plate capacitor are applicable here since the diameter is large.

    Long story short, yes, surface area is very important.


    6 years ago on Introduction

    so how many pF is that? migtht get a bigger bang (but less often) just connecting a bunch of 10kV 3300pF ceramic caps in series (about 60 cents ea). 100 of those = 16.5J assuming full voltage. Dunno how long they'd last in a dead short 2-3 times a minute tho as the plates are very thin.


    you say you have had alot of experience with high voltage devices you should build a marx generator


    10 years ago on Step 10

    just one thing DON'T USE A WOODEN HANDLE wood can conduct electricity use somthing like fibre glass or put the discharge pole onto an RC car

    11 replies

    Reply 10 years ago on Introduction

    Although wood will conduct, there isn't much danger as long as you contact the outside foil layer before approaching the center electrode. If you touched the middle part without a good contact to the outside foil, the electrical discharge might go through the handle and YOU to ground, instead of through the proper path...


    Reply 10 years ago on Step 10

    a good point but better safe than electrocuted also if the pole is damp or has been in a humid room(like a basement) then it might still travel up the pole and give you a nasty shock


    Reply 7 years ago on Step 10

    I probably would have to disagree with that, except for very small voltages (like rubbing your feet on a carpet and touching a doorknob). :D


    Reply 10 years ago on Step 10

    I don't think that's right. I'm pretty sure wood is an insulator, although if theres enough moisture and impurities it can conduct very well.


    Reply 9 years ago on Introduction

    actually if there is a vein of sap that has been dried the right way it can conduct electricity too, especially if carbon/soot lands on it (which is also conductive) wood is a very heterogeneous substance, not good to mix unknowns with high voltage


    Reply 9 years ago on Introduction

     wood does indeed conduct electricity -  in these pictures you see a plain chunk of 2X4 with a grounded screw embedded in one side. there is a hole in the block (near the center of the fractal burn) that has had a high voltage probe embedded in it. when charged, the electricity burns patterns into the wood that resemble fractals.
    the power source for this experiment was a NST, connected to a Cockroft Walton voltage multiplier, to ramp up the volts to 120KVDC - then run through 3- 1 gallon SWC caps, with neg being connected to ground and the screw shown coming out of the side of the block- pos is connected to a probe with a 2 foot pvc handle and ceramic baffles (to allow me to move it when it is on.)
    it looked really cool while it was burning, but no actual flame was present- more like a orange plasma- it also burns from the inside of the block out- very interesting phenomena.


    Reply 10 years ago on Introduction

    I have converted an old go cart flag holder into a discharge wand. Thanks for the safety tip!