Can I Use JB Weld to Build DIY High Voltage Vacuum Feedthroughs?

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Discussion Overview

The discussion revolves around the feasibility of using JB Weld epoxy for constructing high voltage vacuum feedthroughs made from alumina. Participants explore the electrical properties of JB Weld in relation to vacuum applications and high voltage requirements.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant proposes using JB Weld to epoxy alumina pieces together for high voltage feedthroughs, citing reports of its effectiveness in vacuum applications.
  • Another participant requests a drawing of the feedthrough design and inquires about the specific vacuum level being maintained.
  • A participant clarifies that the vacuum level is 10-4 torr and emphasizes the concern about whether the voltage could bridge through the epoxy to the vacuum chamber or nearby objects.
  • One participant shares a link to JB Weld's technical data sheets, suggesting that specifications may be relevant.
  • Another participant advises caution, stating that without knowing the dielectric strength of JB Weld or testing it at higher voltages, it may not be advisable to use it. They also question the necessity of building a custom feedthrough when commercially available options exist.

Areas of Agreement / Disagreement

Participants express differing views on the suitability of JB Weld for high voltage applications, with some advocating for its use based on anecdotal evidence while others emphasize the need for caution and testing. The discussion remains unresolved regarding the appropriateness of JB Weld in this context.

Contextual Notes

There is uncertainty regarding the dielectric strength of JB Weld and its performance under high voltage conditions. The discussion does not resolve whether the epoxy can safely insulate against the specified voltages.

SupaVillain
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I want to build high voltage feedthroughs (vacuum) from epoxying pieces of alumina together, and then epoxying alumina strips on the outside to cover the spaces between. Can I use JB weld, as far as things go electrically? People have reported that JB weld is unexpectedly wonderful for vacuum.

Provided I have the correct amount of alumina per the amount of kv I am applying to it, the electricity won't break down or break through the linings of epoxy will it? It's very expensive to get blocks of alumina and machine them
 
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I think it would be useful to see a drawing of the feedthrough and where you intend to use the epoxy. Also what vacuum are you trying to maintain?
 
A vacuum of 10-4 torr, it's really not a question of design it's more about the epoxy, I am asking if the voltage will be able to move through the epoxy and connect to the vacuum chamber or other nearby objects within the voltages reach.
 
http://www.jb-weld.co.uk/technical-data-sheets
 
Unless you have the specs on it dielectric strength, or test it with at least twice voltage you intend to use I wouldn't use it. Why do you have to make your own feed through? Experimental rule: if you can buy a part that meets your needs at a reasonable price then buy it. High voltage vacuum feed throughs are common accessories for vacuum systems.
 

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