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Re: Hurray, I destroyed my homemade cap!
From: Alfred A. Skrocki[SMTP:alfred.skrocki-at-cybernetworking-dot-com]
Sent: Thursday, November 27, 1997 10:42 AM
To: Tesla List
Subject: Re: Hurray, I destroyed my homemade cap!
On Wednesday, November 26, 1997 6:46 PM Adam
[SMTP:absmith-at-tiac-dot-net] wrote;
> I have enjoyed building my 8" tesla coil, with the exception of my
> homemade oil filled aluminum and LDPE capacitor. The mineral oil was
> really the problem. First, I used a rubbermaid box- leaked. Then, I
> built a plexiglas box cemented firmly with Methylene Chloride- leaked.
> This transformer oil (UInivolt N61) is messy too- it stained my brick
> patio and my wood floors, and it smells kind of like a Jiffy Lube (no
> offense to Jiffylube workers intended).
The rubbermaid box leaking I can expect BUT the plexiglass box should have
worked fine if done right. Are you sure all your joints were properly
bonded? You should also use thick enough plexiglass so you can use nylon
bolts to secure the top and get a sheet of gasket cork from an automotive
supply store to make an oil tight seal once the top is bolted down.
> So today, I destroyed the capacitor all together, plunging plates and
> poly into trashcans full of soapy water. My next experiment is going to
> be a reconstruction of this device, but without the oil. I built a few
> dry capacitors today with my scrap poly and aluminum, and they run fine
> dry at up to 15kV, with very little warming for at least 30 minutes of
> intermittent tesla use (2 minutes at a time, 120mil of LDPE dielectric).
> The only difference was a slightly more noticable ozone production. In
> their favor, they're clean, lighter and easy to repair/rearrange, etc...
> so skip the oil, I'm runnin' dry! :-)
You will run into two major problems by not using any oil, first your
coronal leakage is going to be high and result in less power available to
make sparks with. Secondarily you will suffer edge breakdown as the ozone
deteriates the polyethylene. I built a 6 inch cube capacitor out of 1/8
inch thick polyethylene sheets 6 x 6 inches square with 4 x 4 inch sheets
of aluminum flashing with tabs for the conductor plates. it worked well for
about three months and then started to arc over badly at the edges and the
polyethylene started to melt and that was the end of it's usefull life.
Sincerely
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Alfred A. Skrocki
Alfred.Skrocki-at-CyberNetworking-dot-com
.ooo0 0ooo.
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