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Spark gap materials


jgerlica

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I know there are some coilers out there, so here goes. I am currently using brass bolts ground to a fine point, however I'm looking for something that won't erode quite so quicly. Oh yes, and that is cheap......or better yet free. :D

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My husband suggests unhardened stainless steel, 1/32th thick x 1/8 inch wide. It won't wear down and you usually get it at a lumber yard or machine shop for cheap. You can also use any stainless steel scrap ... like from knives, etc., using verniers if you have them to measure the correct thickness, etc.

 

(he is a master toolmaker)

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Hmm... Maybe tungsten electrodes? Also I think if you used blunt electrodes the ionization voltage would be lower and you could space them closer and waste less energy in the spark gap.

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=67063&item=3822869649&rd=1

 

Edit: Also I should probaly tell you Im no tesla coil expert, Im still working on my first and it only gives small arcs. :-(

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On an off note, if you ever need any caps, I have a large supply.....free as always. Mostly 2700/1000 uf 400 v dc

[Nearly chokes] Did you say free? I might be willing to pay for some sometime in the future.

 

Anyway heres a picture of my tesla coil with a breakout point (nail) and a ground rod.teslacoil2.jpeg

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Tungsten`s quite a good material, a great place to get them almost preshaped is from a darts shop, you can even bolt your conector to them using the back end where the flight stem is screwed in :)

 

I use chrome plated steel door knobs, they work quite well also, what arc damping method are you using, air jet or magnetic?

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Dave, if you go to Latifs they sell steel balti woks there for a quid 50 each, bend the handles off with pliers (they`re only spot welded and break off cleanly) then solder the 2 halfs together with a pencil blow torch. that`ll make the top "toroid" for you, that`s what I made mine with :)

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Well nearly every part of my coil is temporary because of my lack of money. Not only that but the capacitor bank I used which was already too small is now 40% dead. My max spark length is 14" while it should be more than 24" with my power supply. I bought the wrong type of magnet wire so my secondary is to skinny and short.

 

Other than that, I’m happy with it. :D

 

 

Despite what people say, tesla coils can be made with just about anything. (Mine is a good example.)

 

Basically you have a power supply, capacitor bank, spark gap, primary, and secondary. The power supply charges the caps, breaks down the spark gaps and drains the caps through the primary inducing a charge in the secondary. Because the bottom of the secondary is grounded it acts like a cap to the ground. The toroid increases capacitance to the ground.

 

Power supply

So first just find a power supply. If you live in a city there is probably a neon sign shop around. They will normally give you a free neon sign transformer (NST) that is damaged. Try to get one that is rated at 12kv or 15kv. You can also buy one on ebay for about $20 and another $20 for shipping (they are heavy).

 

Secondary

Then find some PVC pipe and magnet wire, 4" dia. is the best for the PVC. The magnet wire can be just about any size from 22AWG to 28AWG. Just wrap the wire around the PVC tell you have 800-1400 turns. You will need a few pounds of the magnet wire so ebay is your best bet. After you wind it just spray on a few coats of polyurethane varnish to make in nice and shiny.

 

Primary

The primary can be just about anything as long as it has about 15-20 turns. Most people use copper refrigerator pipe from a hardware store. It is normally wound flat on a board. I made one like that but it only had 8 turns which was not enough so I just wound some high voltage wire vertically on a plastic container that had Chinese soup in it. :D It’s only temporary but it works.

 

Spark gap

Anything! Two nails sticking out of a board would work. Although it’s best to use more than one segment so it stays cool. You could also vacuum the spark gap. I get MUCH better performance with a vacuum on my single gap.

 

Capacitor bank

Ah, now for the hard part. After you build everything else download teslamap . Then just input all your specs and it will tell you the resonant cap size. You should try to make your bank that size for best performance but it’s not a requirement. Also remember that your caps have to survive the PEAK voltage of your transformer. A 15KV NST will have a peak of 21KV; it would also be a good idea to have the bank rated much higher. 30KV would be nice. You can build "saltwater caps" with clear beer bottles and saltwater or you can buy a large pulse rated cap or you can build a multi mini capacitor bank (MMC). I would suggest The MMC because it can be altered very easily. Your best bet would be here. Tesla map has a built in capacitor calculator so you know exactly how many caps in series and parallel you would need.

 

Toroid

Your toroid can be just about anything too. I prefer aluminum ducting in a donut shape on top of the secondary. Wielding two metal bowls together would probably work too.

 

Tuning

After you put everything together you have to tune it to get the maximum spark length. Basically you just play with all the parts. The primary has to be "taped" in different areas. The position of the toroid also makes a difference along with the distance of the spark gap. Just move everything around and turn it on and off seeing as to what makes a difference.

 

WARNING

Every part of a tesla coil circuit can be lethal! You MUST have bleed resistors across EVERY capacitor. Also the secondary of the tesla coil can build up a static charge whish is not directly dangerous unless you freak out and fall on something sharp.

 

Note my Signature:D

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also the primary coil can be a flat spiral or like and upside down cone (the sort I use) or even another cylinder type former around it in PVC tube :)

 

Yes, also when tuning raising and lowering the secondary can help.

 

Phew, with all that typing I think its time to go get high on ozone. :D

 

Oh ya, I almost forgot. If you have breathing problems don’t operate a tesla coil in badly ventilated areas.

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Oh ya, I almost forgot. If you have breathing problems don’t operate a tesla coil in badly ventilated areas.

Good Point to that man! :)

it`ll also produce NOx gasses (potentialy lethal in a confined area over time).

 

and as an adjunct, it can SERIOUSLY F**K UP expensive electronic equipment!

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Well it would be a good idea to work on some other high voltage projects first. I would start by building a driver for an enrectified flyback and familiarize you with it. That why mistakes wont be lethal and you can learn the do's and don’ts of high frequency high voltage.

 

Also be sure to do many searches on google for telsa coils and such. If you understand a tesla coil theres really no way to hurt yourself.

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a guarded strike rail above the Tank coil and a discharge wand are always a good idea too :)

I`ve found that the KEY component is having a damn good Earth strap (Ground), you`ll cause less damage and get better results with one and less likely to injure yourself :)

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  • 4 weeks later...

Uh, I was just looking through this and I realized that the schematic I made is messed up, Just ignore the writing.

 

Anyway I'm back from a long period of inactivity.

 

Edit: I think I'll just remove it, It does more harm than good. It would be easy to find one on the internet.

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