Building a Tesla gun: photos

(Credit: Rob Flickenger)

Flickenger, an author by day and a 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 from his hometown of Seattle to assist in the process.

(Credit: Rob Flickenger)

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 can see a worker dumping extremely hot liquid aluminium into a container with the Nerf gun pattern. Eventually, it settled into a solidified casting. "We had a pretty good aluminium housing in a couple of evenings," Flickenger wrote on his blog.

(Credit: Rob Flickenger)

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

(Credit: Rob Flickenger)

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 mould 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 aluminium, 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.

(Credit: Rob Flickenger)

Flickenger coated the primary coil of the gun in high-density polyethylene for insulation. "The coil form is a piece of 2.5-inch (63.5mm) ABS pipe wrapped in 30-gauge enamelled wire, then sprayed with polyurethane finish," said Flickenger, who added that many of these components came from Home Depot.

(Credit: Rob Flickenger)

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 volts. From there, the high output feeds into "a centre tapped coil wrapped around the ferrite core of a flyback transformer salvaged from a TV," Flickenger said.

(Credit: Rob Flickenger)

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.

(Credit: Rob Flickenger)

The electrifying end result would surely impress Nikola Tesla, were he alive today.

Via CNET