GardenBanter.co.uk - View Single Post

Broadback · 29-03-2007, 03:36 PM posted to uk.rec.gardening

Gill Matthews wrote:
In article , says...
"Geoff" wrote in message
...
On Sunday I paid £9.99 at a garden centre for a max/min thermometer: it
worked for one day before the iron wire within it sank below the surface
of the blue liquid on the max temp' side and the thing became n.b.g.!

Today I took it back and was refunded the money.

On my way home I called at an ironmonger's and asked them if they had a
max/min thermometer. "In all honesty I could not recommend buying one
from anywhere if it has a blue liquid in it." one of the assistants told
me. I explained what had happened to the one I'd bought and the assistant
said, "It's the b----- EU and a directive about mercury I've been told!
We had some with mercury in and they worked a treat but we had to return
them and were sent those useless things which we've now got rid of back to
the supplier."

Now my question is, "Can anybody recommend a make of max/min thermometer
which works and does not cost more than about a tenner?" I do not want an
electronic one.

Geoff

It was decreed that putting mercury metal in the hands of the great unwashed
( the public) was not a good thing:-)
Pretty nasty stuff -so use blue or red dyed alcohol as an alternative.
Totally accurate and environmentally sound.

except that mercury has a density greater than the little iron pin so it
will float on the surface whereas alcohol has a desnsity considerably less
than iron so the little pin will sooner or later sink. Iron pins so that you
can reset with a magnet.

GillM

I also went down the same road. My next solution was to by a "spring"
type that works like a clock, there are 2 pointers which get moved
clockwise for max temp anticlockwise for min temp. There is a movable
arm with which these arms are "zeroed" whenever required. It works well
and was cheap, however I have doubt to its accuracy, as I am recording
temperatures in excess of 50 degC in my mini greenhouse. So electronic
here I come. However I am unable to source any locally (North
Staffordshire) so I will have to bite the bullet and pay postage.