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
- a neon sign repair shop
- Craigslist (that's how I found mine)
- a used electronics shop
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.
Step 2: Make a Plan
- The transformer is big and heavy
- The transformer is dangerous, and needs to be kept far from people's touch
- The spark is dangerous, and needs to be kept enclosed so nobody can touch it
- Should look like some kind of old lab equipment
I needed a couple of critical parts before I could really begin to plan the details... first of all, I needed a big glass tube within which all the sparking would happen, out of reach of anyone's fingers. My wife suggested a big vase from a florists supply shop, and sure enough, I found the exact thing I was looking for at a flower place called "Aldik" for about $50: a 7" diameter cylindrical vase, 27" tall. Pricey, but it's the single most important safety item, so I went for it. (Later, I discovered a slightly shorter -- but otherwise identical -- vase at Michael's for about half that. Dang.)
For the base, my first plan was to use a window box I had found at Orchard Supply Hardware, which (if used upside-down) had a nice trapezoidal silhouette. I thought maybe I'd use two, one upside-down and one right-side up. So that's what I drew first, along with an idea for incorporating a hand-truck (dolly) into the design so it could be moved around easily.
Step 3: Revise Plan
In addition to more safety, a bigger box would give me a chance to pile all kinds of cool dials and switches onto the front. I could have made such a box, but I don't really have the necessary woodworking tools. (Or skills, for that matter.) Fortunately, I found a plywood box which was absolutely perfect at a thrift store called "Habitat For Humanity," for only $2. It's about 17.5" x 12" x 20", with an open back. It's made of 3/4" plywood.
Step 4: Assemble the Parts
- The transformer (Input: 120v, Output: 15,000 volts, 60mA)
- Cylindrical glass vase
- Two 3' sections of stainless-steel coated rod, 3/16" diameter
- Galvanized ventilation adapter, 8" to 6"
- Glass dome from a ceiling fixture
- Chrome trim ring from electronics salvage store
- 7" flange ring from electronics salvage store
- Lots of pipe fittings: Tees, elbows, joiners, flanges, and plastic lengths
- Valve with red knob
- 2 water supply hoses, braided steel
- Sugar shaker (from 99 cent store)
- Cheap rotating "disco" light (from Walgreens)
- Power cord
- 2 lengths of high-voltage wire (hard to find, but important!)
- Can light fixture with trim ring
- Switch box, switch, cover plate (from salvage store)
- Plasma bulb (from novelty store)
- 2 big ceramic insulators (from electronics salvage store)
- a couple dozen water bottle caps, juice caps, jam jar caps, etc... (these will be the dials)
- 2 handles, simple bent chrome tube ones
- 2 handles, very strong galvanized ones
- Hookup wire
- A dozen or more bottle caps and lids
- A few old knobs, dials, gauges, switches, meters, etc.
- Calculator (from 99 cent store)
- Foldable hand-truck (dolly)
- Spray paints: textured rust, hammered metal, gloss black, primer
Step 5: Make Electrodes
The only thing I used for bending the rods was my bench vise and my hands. As you can see, I'm not exactly a pro at this... but they were plenty good enough.
Step 6: The First Test!
For this test, I did a quick wiring of the power cord to the transformer's input power and ground terminals. Also, using the high-voltage wire, I connected the output insulators to the underside of my electrodes' insulators.
I adjusted the electrode gap to about 1", backed away, plugged the power cord in to my power-strip, and threw the power-strip's switch on. Nothing happened, but I did hear a soft buzz coming from the transformer, so I knew it was trying to do something. Shut off the power-strip, unplugged the power cord, and adjusted the gap (with one hand in my back pocket, a trick I learned from one of the guys at the electronics salvage store; it keeps you from ever creating a deadly circuit that goes through your torso). This time I tried a gap of 1/2", but still no spark. Next, I tried 1/4", and that seemed to be the magic number; I got a beautiful spark, which travelled up the electrodes perfectly! Almost as if I knew what I was doing!
A couple of slight adjustments later, and I was ready to film this test:
Step 7: Create the Supports
This is a picture of one of them; the other side's looked basically the same.
Notice that I had already painted the pipes with a textured rusty paint, to look more like old metal.
Step 8: Attach the Uprights to the Top of the Cylinder
- Support the metal with a block of wood
- Use a centerpunch to mark the hole's location
- Use a small drill bit to make a pilot hole
- Use a larger drill bit to increase the size of the hole
- Use a spade bit to create the finished hole. Don't spin the drill too fast, and don't let it bind against the metal.
Step 9: Add Spinning Light at Top
Originally, I was going to wire this into the main power supply so I wouldn't have to change the batteries a couple of times on Halloween night, but I ended up not having time, so I just used its 3 original AA batteries. Turns out they lasted all night anyway!
Step 10: Add Dials and Gauges
This phase actually started a week or two before Halloween, when I asked my family to please NOT throw away any bottle caps, or jar lids, or things like that, and instead give them to me. They thought I was crazy... and now that Halloween's over, and they didn't see me use them, they're positive I am.
Here's how they would have all been arranged, if I had just started this project a day earlier. I like to see logical groupings, and contrasts between nearby shapes. I tried several arrangements before settling on this one.
Step 11: Create Finished Look of Box
At this point, I felt it looked too plain, so I:
- Masked off everything but 3/4" of each edge
- Painted these edges with a random combination of gold paint and rusty textured paint
- Grabbed some metal corners from an earlier project and screwed them into place
- Added galvanized metal handles, one to each side
- Attached a collapsible hand-truck to the back
Also in this view, notice that I've installed the switch box... It's wired up such that the plasma bulb is always on, but the Jacob's Ladder is controlled by the switch.
Step 12: Plug It in and Throw the Switch!
- Added a reclining skeleton to receive electro-jolts via the braided steel tubing
- Added a motion-sensor skull, which would laugh and look at the Jacob's Ladder whenever I turned it on
- Added various other laboratory props, mostly glass and plastic stuff from the 99 cent store, on a metal cart
- Hooked it all up to a wireless remote controller, so I could turn it on and off from anywhere in the house
It seemed to be a big hit, and I'm hoping to add more sinister props and devices to my "Mad Scientist" laboratory next year...