[Boatanchors] Smart People: Gassy Tubes Reversable?

[hwhall at compuserve.com]

Theoretically....but it wouldn't all come out, and it may take a very long time to get out. Seems to me that it would work better when there is a lot of gas. The less gas, the longer it will take for gas molecules to 'find' the leak that let them in and then wander out. In a near-vacuum, there's a lot of empty space between gas molecules, they won't effectively drive molecules out of the leak because the molecules bump into each other so seldom.? I imagine it would be more practical to set up a glassworking shop to open the tubes, install new getters, pump them down and fire the getters. When one has that technology, one might also even investigate a way to treat or repace spent cathodes.
     

 Wayne
WB4OGM

-----Original Message-----
From: David Stinson <arc5 at ix.netcom.com>
To: milsurplus <milsurplus at mailman.qth.net>; boatanchors <boatanchors at mailman.qth.net>
Sent: Mon, Dec 2, 2013 10:42 pm
Subject: [Boatanchors] Smart People:  Gassy Tubes Reversable?

 
 
 
Some otherwise valuable tubes have taken-in variable 
amounts of gas over the decades.    
NOS transmitting tubes like the 211 are often gassy  
out of the box and cannot be readily "de-gassed"  
like some large Eimacs.   
Even some NOS 1625 and 807 are starting to show signs of gas. 
 
Question:  If a batch of such tubes were put into a large 
vacuum chamber, pumped-down hard and left there for  
an extended time- even a year or more- would the gas 
in those tubes migrate back out? 
 
 
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