Super beefy HV insulator

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Richard Hull
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Super beefy HV insulator

Post by Richard Hull » Thu Feb 08, 2018 7:33 am

I am cleaning out my insulator collection. I have three spares (edit 2/12/18 - only 1 remains) that are identical and for sale. (I had 5, but am saving two for a project I have in mind.)

These are large diameter with a generous 1.5 inch diameter hole up the ceramic interior for a grid post you can add. These are original N.O.S insulators that someone did use but not as intended. (very odd) The silver plated brazing flange is in mint condition. In normal design use, this flange would be brazed, (silver soldered) in vacuum service or soft soldered to a super high voltage capacitor's steel case.

This insulator is superb for a he-man fusor that can handle a 3.5" diameter braze skirt which can be silver soldered to a larger flange. There is a slightly off center hole in the large 3/8 inch N.F. thread top bolt into which you can silver or soft solder a grid stalk.

Yes, real work is involved on the part of the buyer. There is a lot of ways to "skin this cat" for the thinking man to make it fit into a vacuum system. Thus, this is a real deal for the adroit hand making some killer vacuum project where 50-60kv or more is to be brought into a vacuum. My little insulator on fusor IV handles up to 40kv and this bad boy is a monster sitting beside it.

Enough jabber....It is $75.00 shipped anywhere in the U.S. via standard USPS post. No warranty on this as you will either make it go for you or you will screw it up. See images and dimensions in photos. As noted on my store ad rules, I will note ship outside the U.S.

This offer will disappear when the last insulator is sold

Richard Hull
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Insulator3.jpg
Insulator1.jpg
Insulator4 spec.jpg
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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Noah C Hoppis
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Re: Super beefy HV insulator (3)

Post by Noah C Hoppis » Fri Feb 09, 2018 5:30 pm

Richard,
Do you have any info/expertise on the max withstand temp for the ceramic to metal seals on the skirt and center pin?
"No missile ever flew before 10 pm"

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Bob Reite
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Re: Super beefy HV insulator (3)

Post by Bob Reite » Fri Feb 09, 2018 10:20 pm

It would depend on the process used to make the seal. If it was ceramic metallization and brazing, it would be limited to the melting point of the brazing alloy used, as low as 450 C if a soft solder alloy is used. Other seal methods can take temperatures up to 1000 C. Needless to say, I would not push the seal pictured above 400 C, as the original application was probably the feedthrough for an oil filled capacitor operated at no higher than 50 C. In the manufacturing of the capacitor it would have probably been soft soldered to the case.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.

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Richard Hull
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Re: Super beefy HV insulator (3)

Post by Richard Hull » Fri Feb 09, 2018 10:53 pm

My personal belief is that these were manufactured for use in very high voltage large metal capacitor cases. They new saw that use, however.
The skirt could be soft soldered to machined steel fitting and then adapted to a flange using o rings. Or a combination of vacuum epoxy with O rings might be used with no soldering. I would think an ultra low melting silver solder, (braze), like jewelers use would work great on a conflat that had a small machined ridge such that the entire flange need not reach a high brazing temperature before the solder flowed. Like I say, it is a great insulator and vacuum tight for sure and that there are many ways to skin this cat.

Fusor IV uses a Beryllium Oxide insulator manufactured as a shipboard antenna feed through for the radio room. This is definitely not made for vacuum, but has served for years in a vacuum hustling in up to 42kv to do fusion.

Basically if it is oil tight and sea water tight, it is vacuum tight.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Noah C Hoppis
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Re: Super beefy HV insulator (3)

Post by Noah C Hoppis » Sat Feb 10, 2018 6:18 am

Richard, I've sent a PM and Email your way.
"No missile ever flew before 10 pm"

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