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Simple homebrew tesla capicitor (idea check)

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Pr1mus

Tue Jan 15 2008, 07:05PM

Registered Member #1230 Joined: Tue Jan 15 2008, 06:34PM
Location:
Posts: 8

Well, I am kinda making sure you guys think this capicitor is a good idea and kinda throwing the idea out there for others that may want a relitively cheap and effective capicitor.

Instructions to make are simple. Take a meal size (or well, any size) gladware container. Then take the foil tape (real aluminum stuff, not duct tape, doh) and cover both sides of the gladware container, (smoothly and completely as possible) up to just under the rim. The large rim on the gladware containers work like an extra insulator. Also there is a small gap between each container at the botton so that aluminm foil and a wire can be added to complete the circut. Then simply stack and add wires. This is an improvement over the party cup capacitor. The problem with aluminum foil used in that is that it crincles. crincles cause uneven and reduced capacitance, not to mention arcing and other issues (fire??).

Does anyone else see a problem with my design? I think the gladware containers are about 1mm to 0.75mm thick. Surface area is = about 9*9 inches. I think they are made out of some LDPE/HDPE/PVC mix that does work well for a lyden jar to store static electricity to shock friends. Also they are microwave safe! Hopefully tesla coiling them wont cause any issues. This should be fine for 12000 volts, right? I know I'll need alot of them to have the reccomended capacitance for my tesla coil (about 60) but this seems like the best design I have come up with yet. Simple, relitively cheap, and most importantly the materials are redily avalible.

I have 7 of these already made, and I hope to have 15-20 by this weekend for a test. They'll be put up agents my PVC pipe / aluminum foil capacitor (which seems to be filling with a black power... and I also know has far FAR too low of a capacitance)

Capper

Tue Jan 15 2008, 11:05PM

Registered Member #914 Joined: Fri Jul 20 2007, 06:22PM
Location: South Bend, IN
Posts: 85

The problem with that aluminum tape is that the adhesive is an insulator.

Alexandre

Wed Jan 16 2008, 01:15AM

Registered Member #1228 Joined: Tue Jan 15 2008, 01:08AM
Location: Curitiba, Brazil
Posts: 162

Put some pictures to see how it was!

CT2

Wed Jan 16 2008, 02:01AM

Registered Member #180 Joined: Thu Feb 16 2006, 02:12AM
Location: Ontario, Canada
Posts: 187

I don't think that the tape on the aluminum being an insulator is a problem, seeing as how that is how a capacitor works. I think it would definately work, great idea! Now just test it out, and let us know.

Shaun

Wed Jan 16 2008, 02:08AM

Registered Member #690 Joined: Tue May 08 2007, 03:47AM
Location: New Jersey, USA
Posts: 616

It might be a good idea to add oil to the mix in some way. Corona tends to eat through homemade capacitors fairly quickly, especially in TC use. The may appear fine with DC, used as leyden jars, but TCs put a huge amount of extra stress on the dielectric.

I would at least put a little bit of mineral oil or something similar on the inside of each container before you press another one into it.

Nik

Wed Jan 16 2008, 02:51AM

Registered Member #53 Joined: Thu Feb 09 2006, 04:31AM
Location: Ontario, Canada
Posts: 638

Make sure you leave a big gap at the top, surface tracking happens pretty quick with homebrew caps. Also when hot enough (from an arc over) glass becomes a conductor which will ruin your caps and dish.

Pr1mus

Wed Jan 16 2008, 03:00AM

Registered Member #1230 Joined: Tue Jan 15 2008, 06:34PM
Location:
Posts: 8

I'll make one now. I am at my computer and have a web cam right here. I also have the tape and bowl. Yeah, i'll mae additional comments later.

Pr1mus

Wed Jan 16 2008, 04:13AM

Registered Member #1230 Joined: Tue Jan 15 2008, 06:34PM
Location:
Posts: 8

its a gladware container. Dont act so suprised.

Foil Tape. wow.

Now this is of some interest. The foil tape has clear adhesive. Note this if you build this capacitor and yours does not. I'm not sure if it will make a difference, but if it dosnt work, look to the tape

Cover in foil tape. I'm sure you all understand.

Both sides. To conductors seperated by a gladware container - definition of a capacitor.

Stack and wire up. Every other. Sodder and attach to a large diameter wire. Then attach to tesla coil.
Note how the rim seperates the wires. Also note the wires are taped with foil tape to the capacitor. There is also a little aluminum foil between layers so that the bottom of one container is directly connected (kinda) to the inside of the on underneath it.

Finn Hammer

Wed Jan 16 2008, 06:29AM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

all,

About 8 years ago, on the pupman list, the late Marc Metlicka reported great success with his party cup cap.

Similar construction.
You should be ok!

Cheers, Finn Hammer

Pr1mus

Wed Jan 16 2008, 06:16PM

Registered Member #1230 Joined: Tue Jan 15 2008, 06:34PM
Location:
Posts: 8

Also, one more thing. I have had problems in the past with my tesla coil not working at all because I think the voltage was simply going through the capacitor. This problem happened both with soda pop bottles and plastic bag capacitors. I think this should work because the surface is very evenly coated and these are a little thicker and of slightly higher quality plastic. These should be goot for 12000 volts, right? well, I certanly hope so, If I hear the loud buzzing noise from my capacitors again, well, I dont know what I'll do. I dont have the time or money to find 200 sheets of acrylic or polycarb.

I think I saw something somewhere saying that LDPE/HDPE was good to 370Kv/cm. Not completely sure what that means, but I hope these work.

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