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Old 07-20-2010, 01:45 PM
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jeyurkon jeyurkon is offline
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Join Date: Oct 2008
Location: Central Michigan
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Quote:
Originally Posted by leadlike View Post
Well, if luck is on this tube's side-would just putting something over the crack be of benefit? After all, the leak is rather small, so the perceived pressure gradient may not be too extreme. Are there any other relatively available materials out there that are relatively impermeable to the atmosphere but still effectively bond to glass?
Someone pointed out Epotek 353ND to me. It provides a nearly hermetic seal.

Quote:
Originally Posted by Eric H View Post
The Getter is white, this tube has gone to air, it's done.

The only thing now it to look for a replacement, they do pop up now and then you just have to keep looking.
I'm inclined to agree with Eric.

It may have had a small crack to begin with, but under the stress of handling suddenly got much worse as Phil suggests.

I once tried to make a vacuum chamber by sealing pieces, that were assembled in the shape of a soccer ball, with RTV. We wanted to use a flexible material that wouldn't crack. We were unable to achieve a very good vacuum because of the permeability. We ended up overcoating the RTV with an epoxy.

John
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