[time-nuts] Thunderbolt stability and ambient temperature
cfharris at erols.com
Thu Jun 11 09:48:20 EDT 2009
Poul-Henning Kamp wrote:
> In message <4A30457E.9060701 at erols.com>, Chuck Harris writes:
>>> And evaporates and leaks. But yes, I've used water for quick jobs.
>> I just don't know what to say to that! Even a child can put a
>> case of bottled water in a box, and not have it evaporate or leak.
>> I would venture that said case of bottled water will still be full
>> up when the child graduates from college, and has kids of his own.
> Unless UPS or DHL decides to leave your package stranded on a loading
> dock in -20°C for a couple of days.
> In the lab I *might* use water, for shipping I never would.
I thought we were talking about stabilizing the temperature environment
around frequency/time standards? I recall the discussion talking of big
hunks of aluminum, copper, cast-iron engine blocks bought at scrap yards,
and other such unshippable things.
The nice thing about using water as a thermal ballast is you don't
have to ship it specially. It is available everywhere humans go.
If you are worried about it freezing, a 50-50 mix with ethylene
glycol will protect it from freezing down to -40C, or so, though
if we are talking about temperatures like that, it is unlikely that
your precision clock is going to work very well down there.
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