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Started by Dan Koller*
Thu, 20 Aug 1992 15:46
High Vacuum Epoxy
Author: Dan Koller*
Date: Thu, 20 Aug 1992 15:46
Date: Thu, 20 Aug 1992 15:46
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Does anybody know the absolute ultimate lowest obtainable outgass rate of Varian's "Torr-Seal" high vacuum epoxy? Varian Spec. sheets only list confusing figures, after short 130 degree bakeouts. I would like to know if baking out for a week or so at 130 deg. C will help bring the outgass rate below 10e-8 Torr-liter/cm^2/second. I would like to use the epoxy to seal sapphire windows to a small (1 cm^3) glass chamber, pump it down to better than 10e-7 torr, and then seal it off. The problem is that the epoxy seems to be outgassing at a rate high enough to bring the pressure to 1 mTorr in a minute or so. This is to be expected from Varian's published outgass rates, but my question is, can I do better? Finally, if epoxy won't work, is there a better way of attaching sapphire or Silicon windows to glass? Thanks in advance. Danube
Re: High Vacuum Epoxy
Author: William E. Johns;S23015
Date: Fri, 21 Aug 1992 01:12
Date: Fri, 21 Aug 1992 01:12
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In article <1992Aug20.154626.20676@dirac.physics.sunysb.edu> danube@dirac.physics.sunysb.edu (Dan Koller*) writes:
>
> Does anybody know the absolute ultimate lowest obtainable outgass
>rate of Varian's "Torr-Seal" high vacuum epoxy? Varian Spec. sheets
>only list confusing figures, after short 130 degree bakeouts. I would
>like to know if baking out for a week or so at 130 deg. C will help
>bring the outgass rate below 10e-8 Torr-liter/cm^2/second.
> I would like to use the epoxy to seal sapphire windows to a small
>(1 cm^3) glass chamber, pump it down to better than 10e-7 torr, and then
>seal it off. The problem is that the epoxy seems to be outgassing at
>a rate high enough to bring the pressure to 1 mTorr in a minute or so.
>This is to be expected from Varian's published outgass rates, but my
>question is, can I do better?
> Finally, if epoxy won't work, is there a better way of attaching
>sapphire or Silicon windows to glass?
> Thanks in advance.
> Danube
It has been awhile since I worked on a vacuum bench, but I am
reasonably sure that someone makes a special wax that can be
used for gluing things together. This wax was designed for
high vacuum work. I have no idea where you can get it.
Ride Free,
Bill
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