Re: Care of Rare Valves
Glass doesn't flow at room temperature, it's an amorphous solid.
What happens as it's cooled, is that viscosity rises as temperature drops, and at a particular temperature viscosity heads to infinity. Below that in temperature, no flow takes place.
So, valves don't collapse; lenses and mirrors don't go out of focus. Wine glasses ring like a bell (try that with a bell made of lead and you are up for a disappointment unless you cool it with LN2 first!).
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