Re: Hurray, I destroyed my homemade cap!

To: "'Tesla List'" <tesla-at-poodle.pupman-dot-com>
Subject: Re: Hurray, I destroyed my homemade cap!
From: Tesla List <tesla-at-stic-dot-net>
Date: Thu, 27 Nov 1997 09:40:08 -0600
Approved: tesla-at-stic-dot-net


From: 	Bert Hickman[SMTP:bert.hickman-at-aquila-dot-com]
Reply To: 	bert.hickman-at-aquila-dot-com
Sent: 	Thursday, November 27, 1997 2:30 AM
To: 	Tesla List
Subject: 	Re: Hurray, I destroyed my homemade cap!

Tesla List wrote:
> 
> From:   Adam[SMTP:absmith-at-tiac-dot-net]
> Sent:   Wednesday, November 26, 1997 6:46 PM
> To:     tesla list
> Subject:        Hurray, I destroyed my homemade cap!
> 
> 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).
> 
> 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! :-)
> 
> -Adam
> 
> --------------------------------------------------------------------------
> Adam Smith
> absmith-at-tiac-dot-net
> Epoch, Inc. Digital Music Project
> 
> www.tiac-dot-net/users/absmith/                 MP3 Demo Tracks Now Available!
> --------------------------------------------------------------------------
Adam,

Sooner or later, your dry caps will fail due to microdischarges, surface
oxidation, and spark tracking all stemming from electrical  breakdown
effects along the air-LDPE interface, and particularly around the edges
of the plates. While corona may look innocuous, it's actually extremely
hot and energetic.. and hot ozone does very nasty things to LDPE. Please
keep us informed on how long your cap stays operational.

-- Bert --