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QUESTION: I am press fitting an elctrical conector into
(essentially) a steel block. Now I need to seal
the press fit for vacuum. Can anybody stear me
to someone who knows about this sort of thing and
can suggest a sealling method.
ANSWER: How good a vacuum? Do you have to get it out again? Vacuum-grade epoxies are
available.
alt.energy.homepower, there are a lot of posters there that deal with those
type of problems and can help you. A good epoxy may be all you need for a good seal.
There's a lot of things that may or may not work, depending on the
details.
If an epoxy won't do you can use frit, which is a glass powder in a liquid
"vehicle". Apply it like a paste between the steel and (glass? ceramic?)
feedthrough and bake it. Talk to Corning.
Glasses and ceramics can be metallized so that you can weld, braze, or
silver-solder it to things. Ask a tech at an ultra-high vacuum company
like Kurt J. Lesker or NorCal.
If you're not set in your materials you can actually buy ultra-high vacuum
compatible electrical feedthroughs. They usually come with a Conflat
fitting, which has a flange that is bolted in, and knife edges on each
side that cut into a copper gasket. Perhaps you can get dimensional
information from a UHV company and have a machinist cut a knife edge and
blind bolt holes into the steel peice to accept the feedthrough.
Company and product information can be found on-line for free at
http://www.thomasregister.com
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