So, I’ve decided that I want to build my own tabletop tesla coil. I’ve done a little research, and plan to do more in the near future. I was wondering if anyone could give me some advice, or provide a good link to somewhere to help me get started on making one. One specific question I want to know is, considering that this is going to be a small tabletop one (of only say, 50,000 volts or something), about how much will it cost¿ I was hoping that it would only be about $50 (I have more money than that that I could use on it, it’s just I was hoping that it’d be somewhere around that).
Until bbeaty shows up and offers his expert advice (and it really is), I recommend Lindsay Books for guides on how to build Tesla coils. For parts, you might want to check the links in this thread for sources.
Just in case bbeaty’s on vacation, or been abducted by Grays, here’s his Tesla Coil page.
Really! Tesla coil clubs and T-shirts yet. How cool. 
Restores my faith in humanity. 
Peace,
mangeorge
If you’ll settle for 10 or 15 kV, you can build it for cheap. The transformer from a neon sign puts out that much, and if you’re a smart shopper, you can buy one on Ebay for $20. That, a metal coat hanger, and some hardware odds and ends (nuts, bolts, a block of wood) are all you need to be a mad scientist. Doubles as a room deodorizer. Also a poison gas generator for those unwelcome house guests. Here’s a few more links.
Well, I was thinking in the 10-15 kV range, but I want to make a tesla coil, not a Jacob’s ladder.
btw, I found a pic of basically what I want for a finished product: http://www.8ung.at/mrurt/TESL_lg.jpg
Details! I demand details!
Ozone, aka O[sub]3[/sub]. In high concentrations it is noxious and toxic. It is generated by high-voltage apparatus most prolifically when there is a large corona discharge (deep violet light, lots of hissing sounds).
Oh, hell, it’d be easier (and faster) just to shock the bastard with the thing.
Not to mention more satisying.
Until now, I thought they were one and the same. Ten minutes poking around the internet showed me my error.
Not to take away from the other websites listed, but IMO, the best source for practical tesla coil building would be the Tesla Coil Mailing List. Everything is archived so you don’t have to actually join. Find it at http://www.pupman.com
Oh, and here’s a plug for my tesla coil:
Sounds like a 1920s-style death ray. . .
Tesla’s death ray was 1940’s style! He was presenting it to several governments during WWII when he died. Hey, the 1920S STYLE DEATH RAY was just featured in the recent issue of Fortean Times magazine. Lots of cool old illustrations. Be good on a T-shirt.
About Tesla coil information: the situation is a little weird, since the young kids all want to build “lightning machines,” yet the devices are lethal if you don’t know what you’re doing. I think this problem mostly keeps people from posting extremely detailed project plans online. Those who are skilled enough to avoid death by electrocution are also skilled enough to assemble the bits of information from numerous sources. It’s like making your own high explosives: if you need plans, then you probably don’t have the safety training to avoid death.
Costs: buying the parts new would take several hundred dollars. People usually scrounge parts instead. Skilled scroungers can build Tesla coils for nearly zero cost. Use the wire from discarded power transformers to wind the coil on an old hunk of plastic sewer pipe. Ask around at neon sign shops for high-volt transformers that have one burned-out section (and also have one good one, giving half the usual output voltage.) Rather than buying a spun-metal sphere for the top, carve a proper shape from florist’s foam or use a squashed balloon and papier mache, paint it with some epoxy or polyester resin (fiberglas), then glue on a layer of foil.
About that last part: for the very best results, make sure the feed from your secondary is attached to the foil from the inside. Since the net charge inside a sphere is zero, attaching your output there alows a maximum charge to build on the outer surface. You can solder to aluminum foil, but you must use a hot iron, a relatively highly activated rosin flux (standard RMA flux is unsuitable), and SN100 (100% tin) solder.
Pardon my ignorance, but what are tesla coils used for, other than the really cool light show?
IIRC, the spark coil in your car is basically a Tesla coil.
Q.E.D.: Although I’m familiar with the net charge law, I think you’re thinking of Van De Graaf generators, which use such a connection. I’ve never heard of such a connection being used for TCs.
There’s a 1998 patent on using the high frequency, high voltage discharge of a tesla coil to precipitate sulfur dioxide and nitrous oxide from power plant flue gases.
You can also use a tesla coil as a heater for a plasma torch.
They were one of the breakthroughs which made modern radio possible. Up until Tesla’s discovery, radio experiments used low-wattage transmitters and were limited to just a few miles. A Tesla coil is a radio transmitter capable of tens of thousands of watts output. Marconi took Tesla’s transmitter, and the Branlee Coherer receiver, built antennas on either side of the atlantic, and became famous for “inventing” radio. Tesla didn’t object, thinking that when the Tesla power broadcasting system was up and running, he’d mop the floor with the Marconis of the world. Tesla said something like: “Marconi is a good man, let him continue. He’s using seventeen of my patents.” Bad move. Inventors who don’t actively defend their patents will lose battles in court. Years later Tesla took Marconi to court, and lost. In the 1940s the Supreme court reversed the decision, striking down the Marconi patents and essentially making Tesla the “official” inventor of radio. But all the interested parties were dead by then.
Contemporary uses for Tesla coils? Big ones are sometimes used as high voltage power supplies in particle accelerators and lightning experiments. The DC kilovolts power supply in all TVs and CRT computer monitors is essentially a Tesla coil with a diode on its output. For fluorescent tubes and compact fluorescent bulbs, the “solid state ballast” is a high frequency coil. Yes, ignition coils in cars are Tesla coils; relying on resonant stepup effects (as opposed to simple induction coils which are merely transformers employing turns-ratio for high voltage step up.)