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RE: Hurray, I destroyed my homemade cap!




From: 	Adam[SMTP:absmith-at-tiac-dot-net]
Sent: 	Thursday, November 27, 1997 12:56 PM
To: 	Tesla List
Subject: 	Re: Hurray, I destroyed my homemade cap!

Bert wrote:
>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.

Yeah, I know all about that :-)  Back in the eighth grade, I made some 
caps from pepsi bottle material (PET) for my first TC ever, and after a 
few weeks use the plastic had these fractal-esque lightning-like 
branching patterns all over it, especially from the corners of the 
plates.  It was actually quite beautiful and artistic, and I included the 
etched dielectrics as part of my display.

So then, how about solid corona protection, like paraffin wax?  I could 
get this cheaply at the grocery store, melt it in a double boiler and pot 
the cap.  This would make the cap a lot more difficult to repair, but if 
I over engineered it in the first place it should survive a few years of 
Tesla use, right?.  I am using 120mil of very high quality LDPE (4 x 
30mil) and operating at 9kV, so my cap is not likely to blow anytime 
soon.  Mostly I just want to make something without that horrible oil!!! 

-Adam

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Adam Smith
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Epoch, Inc. Digital Music Project

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