Another HV Feedthrough

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Nicolas Krause
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Another HV Feedthrough

Post by Nicolas Krause »

I've been slowly assembling the bits and bobs necessary to build a HV Feedthrough and I finally had enough that a dry fit to test some components made sense.
signal-2021-08-31-100802_001.jpeg
The feedthrough port was bored out to the correct dimensions on the lathe.
IMG_1745[1].JPG
IMG_1746[1].JPG
This is essentially a blatant copy of Liam David's excellent work documented here so I see no need to repeat all the information he provided. I have some plans to modify things a little with the high voltage connectors at the end, but that's for another day! Right now I'm missing a few o-ring seals and some high voltage connectors so I'll likely order those when time permits.
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Finn Hammer
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Re: Another HV Feedthrough

Post by Finn Hammer »

Looking great Nicholas, just yesterday, I got delivery of a batch of quartz glass tubes, 19mm x 25mm, with flame polished ends, for the same purpose.
I look forward to try this design.

Cheers, Finn Hammer
John Futter
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Re: Another HV Feedthrough

Post by John Futter »

Nicholas , Finn
IMHO it is better to use Pyrex tube Pyrex is very slightly conductive compared to Quartz so you get a reasonable voltage gradient along its length
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Jim Kovalchick
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Re: Another HV Feedthrough

Post by Jim Kovalchick »

I have used borosilicate to 60 kV.
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Liam David
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Re: Another HV Feedthrough

Post by Liam David »

Great start Nicholas. Looking forward to your progress.

I've used the quartz up to 70kV in vacuum and 60kV in plasma, although I do have a larger version in the works.
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Finn Hammer
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Re: Another HV Feedthrough

Post by Finn Hammer »

@John,

I see a spiral of conductive ink, like on the Van de Graaff generators of yore, but where to get that these days?

Cheers, Finn Hammer
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Richard Hull
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Re: Another HV Feedthrough

Post by Richard Hull »

Try...

http://www.creativematerials.com/produc ... fQQAvD_BwE

They offer resistive carbon inks.

I added this to the "Base level source" fourm in the for sale area.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Nicolas Krause
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Re: Another HV Feedthrough

Post by Nicolas Krause »

Just a quick update with something I thought was neat. I've been a bit slower than I'd have liked to have been with some Fusor things, I got a bit distracted by some math I was working on and then I started a new job, but I've been making progress on my feedthrough. I had an idea, I think inspired by some postings here and also having seen some old timer welding tricks on youtube, to bend a tungsten welding rod into a grid shape. I was using a MAPP torch to heat the rod, and I managed to create some tungsten oxide! It was actually a bit yellower immediately after heating, but you can still see it a bit in the attached image. I think if I want to bend a rod like this I'll have to break out the TIG welder so there's some sort of inert atmosphere around the rod. For now I'm just going to try using some skinnier tungsten wire I've ordered, that I can bend into shape manually.
IMG_1839.JPG
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Richard Hull
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Re: Another HV Feedthrough

Post by Richard Hull »

A couple of years ago there was an offer of free Tungsten wire in the trading post. I got some. Did you see the offering? Is the fellow who offered it still here?

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Dennis P Brown
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Re: Another HV Feedthrough

Post by Dennis P Brown »

I've had success with steel welding rods as an electrode; no melting issues and only minor sputter coating issues - but that is an issue to be aware of.

These are rather easy to bend into shape (resist work hardening), and cut.

Your electrode is looking good.
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Nicolas Krause
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Re: Another HV Feedthrough

Post by Nicolas Krause »

Hi Richard,

I think I did see the post but at the time did not order any, a year or so ago I managed to appropriate some tungsten wire of my own of a suitable gauge for a grid.
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