Tesla Coil Build Thread

[USAbro]

If Polypropylene, sure.

Sheets are just more efficient/effective for building capacitors out of since you can parallel and series them much better.

Other plastics suffer from dielectric heating (from losses) and breakdown... sometimes catastrophically.

I meant the big plastic bins. I could cut the walls out and make large capacitors which could be wired in parallel. Can this type of plastic cap be used for 16000 htz? http://www.amazon.com/Sterilite-198...18960821&sr=8-1&keywords=Plastic+storage+bins
You've been of great help-Sigurthr and Upaa.

 

[Sigurthr]

Not sure what kind of plastic those tubs use, could be polyethylene or polycarbonate blend or even polyvinyl. They'll all work to some extent, but polypropylene are by far the best since it has the lowest loss and best dielectric coefficient.

I'm always glad to help when I can.

 

[USAbro]

So lets clarify. Will they work with the high frequency for the tesla coil? Flyback transformer-plastic tubs on amazon (caps)?

 

[Sigurthr]

So lets clarify. Will they work with the high frequency for the tesla coil? Flyback transformer-plastic tubs on amazon (caps)?

Regardless of the type of plastic, or even the type of capacitor you use, you have to rectify the AC into DC using a full wave bridge of RF fast High Voltage diodes for it to work for a tesla coil. No matter if it is 1KHz or 1MHz. If it is above about 200Hz, you need to rectify it.

 

[USAbro]

Could you tell me a simple way to rectify it. Like what parts and how to wire it????

 

[upaa27]

Could you tell me a simple way to rectify it. Like what parts and how to wire it????

Get diode's rated for your voltage and double that, and find ones that say that they are fast.

Make a rectifier. There are plenty of instructions for it online.

 

[USAbro]

Get diode's rated for your voltage and double that, and find ones that say that they are fast.

Make a rectifier. There are plenty of instructions for it online.

Can they be bought at radio shack you think?

 

[upaa27]

Can they be bought at radio shack you think?

You can find them online. RadioShack won't have those diodes

 

[nospin]

Why don't you shoot for old broken microwaves

That's the Biggest Bang for your buck!
The MOT has scary power And the diodes and caps are practically bullet proof and they are what I used in
my half wave rectifier in my coil

I put an ad in a forum like CL and ended up with at least 8 and 1 newer high end SS model with a bad door switch thats in my kitchen now!

 

[Down with Umbrella]

If I may step in for a second I have a question about top load construction.

Materials I have:
1 section of "rigid" 4" dryer duct.
1 roll of 3" AL tape.
2 8(ish)" pie pans. I also have two steel ones to roughly the same size.
3/8" nylon threaded rod. Pvc end cap for top of secondary.
So far I have been reading up on Deep fried neon and HVtesla and I'm not sure exactly which method will work best. I chose nylon hardware to avoid creating break out points.

should I stretch the duct out? Will the steel plates hinder anything?
How should I connect the secondary coil to the top load? I was thinking of using a nylon bolt for a pinch point between the enamel magnet wire and pie pan.
After should I coat the whole thing with AL tape or leave the ribs of the duct exposed. I've seen many variations of top loads often conflicting.

 

[upaa27]

Why don't you shoot for old broken microwaves

That's the Biggest Bang for your buck!
The MOT has scary power And the diodes and caps are practically bullet proof and they are what I used in
my half wave rectifier in my coil

I put an ad in a forum like CL and ended up with at least 8 and 1 newer high end SS model with a bad door switch thats in my kitchen now!

He needs fast diodes. Those are for 60hz. I think they might make switched mode ones nowadays though but those are hard to find.

 

[nospin]

Hey

I have made a 4x18 a 6x24 and am starting a 8x30 all from Al dryer duct

The steel one's will be rigid and thats good, My 4" one is steel pie pans

Just attach the pie pans to each other, I used pop rivets, easy! drill a center hole

stretch out the duct with two people, about 4 feet, now start to compress one side only
right around the pan edge to form the circle, adjust as needed to use all the tube and make it consistant, use some duct tape along the seem when it looks good.

attach Al tape in radial strips from the center top around the edge and back to the center bottom, like spokes

use a large spoon with your thumb in it to smooth it out, its magic!

I use big bolts to hold mine on, but that's not easy as you have to have the HV inside
the secondary and that's normally a coil killer!

I like having threaded rod at both ends for winding and for the ground and the HV ends
This makes a solid connection for both. I did it using epoxy resin to insulate the bolt heads

 

[USAbro]

Okay guys I getting sick of the RF flyback idea. So I'm gonna ask my local shop to see if they have any old NST's.

Besides that I have a question. I just made four capacitors that are sheet caps. I used that plastic (I'm not sure what kind it is) that comes from toy boxes. Like an rc car at Wal-Mart. The kind the box clear viewing shields are made from. I used aluminum tape for the metal. I tested them with the ballast (3.7kv) it is arcing straight through the plastic. However, when I touch the terminals to the cap, and then short two other wires off the cap, it makes the snapping of the spark gap. So I'm still unsure of what to make the caps out of. Any suggestions. I can't afford a lot, as I am already trying to get a Neon Sign Transformer, so any home made ideas? Also, will the leyden jars work for the NST rig?

 

[nospin]

He needs fast diodes. Those are for 60hz. I think they might make switched mode ones nowadays though but those are hard to find.

Really?

Lets hear about your SGTC?

 

[USAbro]

Nospin, I really thinking about that Franceformer. First I'm checking to see if I can get a free one though.

 

[Sigurthr]

Okay guys I getting sick of the RF flyback idea. So I'm gonna ask my local shop to see if they have any old NST's.

Besides that I have a question. I just made four capacitors that are sheet caps. I used that plastic (I'm not sure what kind it is) that comes from toy boxes. Like an rc car at Wal-Mart. The kind the box clear viewing shields are made from. I used aluminum tape for the metal. I tested them with the ballast (3.7kv) it is arcing straight through the plastic. However, when I touch the terminals to the cap, and then short two other wires off the cap, it makes the snapping of the spark gap. So I'm still unsure of what to make the caps out of. Any suggestions. I can't afford a lot, as I am already trying to get a Neon Sign Transformer, so any home made ideas? Also, will the leyden jars work for the NST rig?

The cap arced through because the dielectric wasn't thick enough to withstand the voltage, it will still hold a charge at voltages lower than the punch-through voltage. It is unsuitable for tesla coil work, and a fire hazard for anything else now. Toss it. I believe I said earlier the plastic should be around 1mm thick per layer.

Really?

Lets hear about your SGTC?

He has a point; the MODs I tested a while back were pretty capacitive to tens of KHz. I only have one left but if need be I can test it on my 30KHz supply. They won't die from it because they have much higher reverse breakdown voltages and forward current ratings than the application requires, but they'll still pass a fair amount of reverse current from a 16KHz supply. Another issue all together is the forward voltage drop on those diodes can be rather hefty, tens of volts at minimum, and I think his ballast only puts out 30V under load. After the Vdrop it's likely he'd see essentially no current flow once loaded.