You've seen Jacob's Ladders in Frankenstein movies: you know, the gizmo with the two antenna things sticking up, and a bright arc of electricity rising between them, and making that wicked crackly sound. Nothing says "Mad Scientist" like this thing... and although it can be dangerous if you're not careful, it's actually not that hard to build. At its heart, it's really just a big ol' neon sign transformer (about the size and weight of a car battery), and a couple of thick wires... the rest is just safety stuff; housing, a switch, and insulators to make sure the spark only happens between the wires, and never travels through someone's body.

Yes, safety is incredibly important with one of these things... it's a lot of voltage, and could actually be fatal if you let it pass through you. So DON'T let it pass through you! I'll be mentioning safety precautions as we go, but the biggest one is this: BE CAREFUL. Never touch any part of the device while it's running, and double-check, triple-check, quadruple-check that it's unplugged before you approach it. Just because it's not sparking doesn't mean it's safe!

Other than the basic transformer, wires, and some safety stuff, it's all just window dressing... You can put a lot of knobs, dials, pipes and such all over it -- I also added a little plasma lightbulb which radiates pink lightning from its filament to its glass bulb (I saw a cool prop where someone had done that, and decided to borrow the idea).

Much of what I did on this prop was unique to my particular set of parts; as you look around for your own pieces, you'll probably need to adjust a lot of things, and improvise. But that's a good thing; in fact, it accounts for about 90% of the fun!

Step 1: Find a Transformer

You need a neon sign transformer... But newer neon signs don't have the right kind of transformer, so you have to find an old used one. Try looking in these places:
  • a neon sign repair shop
  • Craigslist (that's how I found mine)
  • a used electronics shop
Be sure to let them know that you're planning to make a Jacob's Ladder; they'll most likely know exactly what you're up to and point you to an appropriate one. And they'll probably give you some great advice as to how to get the most out of it without electrocuting yourself.

I got mine from a guy who WAS going to make a Jacob's Ladder for Halloween, but then decided he didn't have enough time this year.  It's pretty beat up, but I like it.
<p>Fabulous looking Jacob's Ladder. Great documentation!</p>
<p>How long can you run this Jacob's Ladder? Does anything heat up that could be a danger?</p>
As I mentioned in the other reply, heat and gas buildup due to the closed top made me leery of running it continuously... But if the top was open, I think it could run for hours and hours nonstop. The metal electrodes will get all pitted and scorched, but they're easily replaced.
<p>Great job! I'm thinking of building one for a high school production of Young Frankenstein. Could you use an acrylic tube instead of the glass one? </p>
Acrylic would be great, because I've broken every glass tube I've ever bought for this thing. I'm just worried that it wouldn't withstand the high temperatures, but that's just intuition; I have no data one way or the other.<br><br>Incidentally, whether the tube is glass or acrylic, having an open-ended tube would probably be better than the closed ones I've been using, due to heat and gas buildup.<br><br>(Also incidentally: if you're local, I'd be happy to donate my (tubeless) prop to your production... That way you wouldn't have to try to find one of those old-style electrical transformers...)<br>
Great job, quick question- what did you use to connect the couplers to the ceramic insulator?
The ceramic insulators I found each included a huge bolt going up through the center... Those couplers were chosen to match the thread on the insulators' bolts. Is that what you were asking about? (Sorry about the slow response to the quick question!)
If you have trouble finding high-voltage wire, look in an auto supply store (or a junkyard) for spark-plug wire. BTW, nice call on those threaded-rod couplers. They make much more &quot;official&quot; looking terminals than the nuts, bolts and washers that I used.
Nice! A question ...You don't have any way for air to escape the enclosure correct? do you ever have a problem with it arcing because of that? I had read that you need air movement to keep the ionized air fresh.
Thanks, rredmon... To answer your question, I did make sure there was at least SOME way for air to flow in and out of the cylinder. If you look closely, you'll see that the bottom of the glass actually rests on some bolts, which gives it a bit of a gap. It seemed to be enough... plus, I was careful not to leave the device on for any length of time.
I see. I made one a few years ago and have never been happy with my enclosure, a cracked at the bottom glass candle holder. I drilled a hole in the top and have it resting on some ceramic pads, but I've always wanted a perfectly cylindrical glass tube enclosure. What I have is tapered. It's just that my budget is nonexistent and long glass tubes are expensive.
Congratulations on being a finalist in the Halloween contest!!! Can&rsquo;t wait to see if you win! Good luck!
Very nicely done! All the extra 'decoration' really add to it. Can't wait until you can add all the knobs and switches!

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