On 24 Jan, 19:33, Mike Tullett
wrote:
On Thu, 24 Jan 2008 19:18:24 -0000, Nick Gardner wrote in


My sheathed maximum thermometer has (ever since I just caught the edge of it
on the Stevenson Screen whilst resetting it) developed a small break in the
mercury about half-way along the mercury column itself. I have tried
shaking, spinning and just about everything else I can think of to get the
gap to move to the end of the column away from the bulb but it just sticks
there.

At the moment it isn't worth using as it is over-recording by about 1.5C, so
I am having to rely on the Davis AWS for my maximum temperatures (though to
be honest they were always within +/- 0.2C of each other).

Anyone have ideas on how solve this one?

When that happened to me I resorted to gently heating it under the hot tap,
making sure it just filled the cappilary tube and up into the wider part at
top of the stem. *Great care is needed to avoid it breaking though.

--
Mike Tullett - Coleraine 55.13°N 6.69°W *posted 24/01/2008 19:33:34 *GMT


I agree - that should do it, and I've done this myself before now
quite successfully. You can heat sheathed thermometers up quite a way
beyond the end of the scale to ensure the mercury column rejoins, the
reservoir at the end of the stem is sufficient by design to withstand
this sort of heating and (unless you put a blowtorch to it) you
shouldn't be at much risk of bursting the thing. Also applies to
spirit minimum thermometers, which 'bubble' by themselves quite
regularly.

--
Stephen Burt
Stratfield Mortimer, Berkshire