[HN Gopher] "Faraday Wax" - recreating old school high-vacuum epoxy
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"Faraday Wax" - recreating old school high-vacuum epoxy
Author : zdw
Score : 19 points
Date : 2021-05-29 20:03 UTC (2 hours ago)
(HTM) web link (www.eevblog.com)
(TXT) w3m dump (www.eevblog.com)
| knolax wrote:
| So what replaced this stuff in modern applications? Better
| couplers? Special epoxy?
| analog31 wrote:
| A number of things. Metal seals, welded and vacuum brazed
| joints, a variety of good epoxies. Even good O-rings. And
| helium leak chasers, so you can actually find and correct
| leaks.
|
| To get down below a certain pressure, you have to heat
| everything and "bake out" residual volatile materials. This
| precludes a wax from even being tested at the lowest pressures.
| wiml wrote:
| We also figured out how to make direct glass-to-metal joints at
| some point. Widely used in mass-manufactured stuff, but I think
| you can also buy just a glass-to-metal transition or
| feedthrough by itself if you're doing custom glasswork.
| wyager wrote:
| Back when I worked in a vacuum lab we used copper O-rings
| between tubes, and the edges of the tubes had a knife edge to
| cut into the copper.
|
| It was pretty expensive - you're only supposed to use each
| O-ring once. We had a big box of them that we'd occasionally
| send off to recycle.
| lostlogin wrote:
| After searching about I stumbled on this interesting history of
| vacuum devices.
|
| One of the dangers in early experimentation was the church,
| because of course.
|
| https://cds.cern.ch/record/455984/files/p281.pdf
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(page generated 2021-05-29 23:00 UTC)