Culture

Building a Tesla gun (photos)

Crave explores the creation of the Tesla gun, a DIY shooter by Seattle mad scientist Rob Flickenger that tickles (and zaps) our fancy.

Christopher MacManus

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Christopher MacManus

May 15, 2012 6:59 a.m. PT

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Mad scientist

After reading the graphic novel "The Five Fists of Science," Rob Flickenger set out to create a weapon similar to the Tesla coil-packing gun wielded by grandfather of electricity Nikola Tesla on the book's cover.

Flickenger, an author by day and mad scientist by night, wanted to create a dastardly weapon capable of firing thousands of volts of electricity. He enlisted several crafty (and courageous) people in his hometown of Seattle to assist in the process.

Click through our gallery to see the weapon's innards, and a shot of the sparks in action.

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It begins..

Since an electrical weapon needs to be safe and stable, Flickenger commissioned a fellow from the industrial-arts studio Hazard Factory in Seattle to create the housing for the Tesla gun. Using the sand-casting method, the duo made the shell of the weapon from an ordinary Nerf gun. In this image, we see a worker dumping extremely hot liquid aluminum into a container with the Nerf gun pattern. Eventually, it settles into a solidified casting. "We had a pretty good aluminum housing in a couple of evenings," Flickenger wrote on his blog.

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Before and after

A sand-casting doesn't always come out perfectly, and the next step required Flickenger to use a large Fadal vertical milling machine to cut away the excess aluminum from the molding. The machine sprays a coolant on the cutting surface during the milling process, which makes grinding away unwanted metal relatively easy.

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What makes it tick

Even Mr. Wizard would do a double take at the inside of this beautiful DIY weapon. Flickenger used a combination of electrical components to create a Tesla coil gun capable of emitting 20,000 volts.

"The heart of any spark gap Tesla coil is the high-voltage switch," Flickinger wrote on his blog. "It needs to be able to withstand repeated switching events of many thousands of volts at an instantaneous current of a couple of thousand ampere, generating more than a little bit of heat along the way."

Flickenger created a high-voltage switch (the white cone-shaped component) with assistance from Metrix Create:Space, a public workshop in Seattle. The process required using a 3D powder printer to define a mold of the switch. The mad scientist then used a slip-casting process to create the porcelain housing that houses tungsten welding electrodes.

"Since the housing is made of highly conductive aluminum, electrical connections are made with 40kV high-voltage wire," Flickenger noted.

The gun packs several other components, including six capacitors (942C20P15K-F by Cornell Dubilier) and some bleeder resistors to safely store energy.

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Homemade coil

Flickenger coated the primary coil of the gun in high-density polyethylene for insulation. "The coil form is a piece of 2.5-inch ABS pipe wrapped in 30-gauge enameled wire, then sprayed with polyurethane finish," said Flickenger, who added that many of these components came from Home Depot.

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Power supply

Powering a Tesla gun sounds like an extraordinary task, but in reality Flickenger uses a simple 18-volt lithium ion drill battery encased in a 2.5-inch PVC plumbing end cap. The drill battery powers a ZVS driver circuit, which leads to a flyback transformer that converts those 18 volts into 20,000. From there, the high output feeds into "a center tapped coil wrapped around the ferrite core of a flyback transformer salvaged from a TV," Flickenger said.

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The finished product

The doughnut-shaped tube, also known as a toroid, prevents the Tesla coil from destroying itself by controlling the direction of the electrical arcs away from the components. The toroid also heightens the length of the electrical streams, as seen in the next image.