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Re: Diff pumps cleanout

Posted: Wed Sep 13, 2017 8:10 pm
by Dennis P Brown
The issue I have had with Indium is that it is single use. Has to be replace each time the components are dis-assembled. Also, steel expands a lot with temperature and Indium does not easily accommodate such expansions without being deformed in a permanent manner (when further compressed, it is going to have issues when the metal re-contracts) - that could be an issue for a diffusion pump that cycles. May not be an issue but do consider that.

Unless the issue is cryogenic mating surfaces or ultra-high vac (10^-7 and higher), I have no issues with low cost gaskets.

Re: Diff pumps cleanout

Posted: Thu Sep 14, 2017 3:35 am
by ian_krase
Isn't it also imminently remeltable though?

Re: Diff pumps cleanout

Posted: Thu Sep 14, 2017 4:16 am
by Jerry Biehler
Yep, it is. Its very soft too, you can put dents into it with your fingernail.

Re: Diff pumps cleanout

Posted: Fri Sep 15, 2017 5:32 am
by Richard Hull
Indium is one of the softest of all the elements. I makes lead look like stainless steel. Some of the nasty metals like those on the extreme left of the chart might be softer but are unusable structurally or for most all purposes in the real world.

You can stand over a molten vat of indium, 153 deg C, with an inverted funnel and hose leading to your nose and snort th' stuff as it has, effectively, no vapor pressure until it gets near is monstrously high boiling point 2000 deg C.....3000+ deg F

You can write very nice, long, conductive paths on paper or wood with a stick of indium metal. I have had my hands turn silver handling the stuff. According to the "Rare Metals Handbook" there is no recorded case of industrial Indium heavy metals poisoning. As with many metals, there are rare instances recorded of contact dermititus with long term repeated handling.

Aluminum has far more industrial contact dermititus instances reported.

Indium is a fun metal, one of my favorites, and I have about 5 kilogams on hand.

Richard Hull