Hello All,
I have a quick question: How long does it take average two-part epoxy to stop (or lessen) most of its out gassing? Below is a photo of how we have setup our grid. I've insulated the stalk of the grid with the epoxy two-thirds of the way up to get past the collar in the chamber, which is close to the stalk.
Thanks,
Ed
Average Time for Epoxy to Out-gas?
- Ed Meserve
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Average Time for Epoxy to Out-gas?
Ed Meserve
- Nick Peskosky
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Re: Average Time for Epoxy to Out-gas?
The time length of volatile out-gassing is completely dependent on a wide range of factors. When considering whether or not to use something within vacuum applications you must first use the "smell" test, if you can whaff vapors from a compound towards your nose at atmospheric pressure and detect a scent, chances are that this is not a good candidate for use in a vacuum environment. Outgassing rate is product of the epoxy's constituents vapor pressure, chamber temperature and ultimate vacuum pressure attained. NASA compiles a list of epoxy/adhesive/lubricant suitability for vacuum use which can be found in the following link:
http://outgassing.nasa.gov/
Depending on the epoxy you selected it could be a day or two or continue indefinitely, especially under exposure to plasma due to its vicinity to the inner grid. Hope this sheds some light on your question. Had you considered using alumina stalk to avoid the use of the epoxy altogether or minimize its use?
http://outgassing.nasa.gov/
Depending on the epoxy you selected it could be a day or two or continue indefinitely, especially under exposure to plasma due to its vicinity to the inner grid. Hope this sheds some light on your question. Had you considered using alumina stalk to avoid the use of the epoxy altogether or minimize its use?
Nick Peskosky
NPeskosky@gmail.com
"The whole of science is nothing more than the refinement of everyday thinking." - Albert Einstein
NPeskosky@gmail.com
"The whole of science is nothing more than the refinement of everyday thinking." - Albert Einstein
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Re: Average Time for Epoxy to Out-gas?
I used Hysol 9497, high temperature epoxy (up to 180 deg. C.)
To reduce outgassing, the way you cure the epoxy is very important. Just mixing the components and letting it cure at room temperature will make the epoxy outgass for a long time.
Curing the epoxy at 100 deg. C for one hour gave better results, E-5 mbar within a few minutes.
To reduce outgassing, the way you cure the epoxy is very important. Just mixing the components and letting it cure at room temperature will make the epoxy outgass for a long time.
Curing the epoxy at 100 deg. C for one hour gave better results, E-5 mbar within a few minutes.
- Ed Meserve
- Posts: 74
- Joined: Wed Oct 19, 2011 4:51 pm
- Real name: Ed Meserve
- Location: Maine, USA
Re: Average Time for Epoxy to Out-gas?
Nick,
Thanks for the NASA link. Checked out Uline, the manufacturer of the epoxy I used; it wasn't listed.
Jeroen,
Thanks for the curing tip. I will try curing it at 100 deg. and compare the results.
Ed
Thanks for the NASA link. Checked out Uline, the manufacturer of the epoxy I used; it wasn't listed.
Jeroen,
Thanks for the curing tip. I will try curing it at 100 deg. and compare the results.
Ed
Ed Meserve