#fancy builds

Not shown: that time I accidentally touched the plate on top, it was definitely... an... experience...

As an avid builder of big stupid things this is probably the biggest, stupidest, thingiest thing I’ve ever worked on. It’s a massive spark gap Tesla coil, and I haven’t been able to try running the whole thing 1) because it’s a bit unsafe to do alone; 2) there’s still things that need to be reinforced and fixed; 3) I’m mildly scared of it. Seriously, I tested the power supply alone and when I turned it on, the lights in my house started flashing. Anyways, since it’s still a current-in-progress project, I have a ton more photos of the build and all, including all our very sketchy choices.

And, of course, to use as chokes inductors, we have 3 rewound MOTs, because at this point why not. 

The Flashlight of Doom, no I will not elaborate on this

When you test only the power supply and stuff starts burning, that’s when you realize that you might be dealing with a whole ‘nother level of power here...

So yeah, this is a Marx Generator-this stack of capacitors, resistors, and spark gaps can get you some pretty darn impressive sparks (out of a 12V battery), and it also is ridiculously loud whenever the whole thing fires. Adding some spooky unfinished-build pics as well because this was built solidly in my “what is making things structurally sound???” phase, and it’s kinda funny to look back on it a year and a half later. You can also see the ZVS driver for a TV flyback transformer, that we used to get 12VDC up to much higher voltages-might add more about it later, because flybacks are incredibly fun to mess around with.

The next iteration on the coilgun was this device here. Instead of launching projectiles from a barrel, the challenge I made for myself this time was seeing how high I could launch something-I swapped the barrel and coil for a “pancake” coil of solid, thicker wire. I also made some modifications to the circuit so firing could be more controlled: in place of the first spark gap, I added a “control panel” connected by long wires, with a button for firing and another for switching between charging and firing modes. I swapped the second, big spark gap, for an SCR, which did a better job of handling high currents than my sketchy spark gap. I added relays as well to prevent the circuit from firing while the capacitors are charging as another safeguard-there’s two of them; the first controls power flowing to the circuit for charging and normally stays closed, and the second controls firing the SCR and is normally open.

CONTINUED COILGUN STUFF: To switch and close the circuit, this design uses 2 spark gaps-one’s on top of the capacitor bank and serves as a “firing switch”, and the other, the one shielded by the brick, closes the circuit-this gap serves the same purpose as the silicon controlled rectifiers used in many coilgun designs. This gap handles a very large discharge when the coilgun fires, so it had to be able to withstand that repeatedly. We originally considered using 2 aluminum pieces close together with something separating them in the middle connected to a string, which could be pulled away from a distance, letting an arc jump to close the circuitwe called this the mousetrap switch. This didn’t work out very well-the switch was unreliable and awkward for us to try and control. We made a more solid solution, with a metal frame and adjustable screw serving as electrodes. This was also nice because we could now easily adjust the gap distance with the screw, and it ultimately performed really well.