"Chris Hogg" wrote in message
...
On Wed, 4 Oct 2017 09:51:17 +0100, "NY" wrote:

wrote in message
...
The stainless thermos is not the same as a vacuum flask,a good vacuum
flask will keep water at a higher temperature for 24 hours,the stainless
only keep hottish for 8 to 10 hours,if you read carefully you will see
that stainless thermos never say it's a vacuum flask otherwise trading
standards would be straight on to them.
hope this help Alan231

Aren't stainless steel flasks vacuum flasks - the only difference being
that
they are made of metal rather than glass which is more fragile. Or do
steel
flasks have insulation padding between the inner and outer skins, rather
than a vacuum?

I had the same thought. Whether the OP means any form of SS generic
'thermos' flask, or specifically those made by Thermos, isn't clear.
There are plenty of adverts out there for SS vacuum flasks. OTOH it
wouldn't surprise me if the cheaper ones are not true vacuum flasks
but are as you describe, with some form of insulation material between
the walls. Having said that, I see the supposedly genuine Thermos
flasks on the John Lewis web site don't describe themselves as vacuum
flasks, although other flasks there, do. http://tinyurl.com/ybqtzf39

I always assumed that the reason hot things cool a little faster in SS
flasks was because SS has a thermal conductivity roughly ten times
that of glass.
https://en.wikipedia.org/wiki/List_o...conductivities and
scroll down a long way.

Yes, presumably when the inside skin heats up, the heat conducts to the neck
of the flask (AIUI, the only part where there is contact between inside and
outside skins).

I can never look at one of the modern wide-necked stainless steel flasks
nowadays without remembering a woman that I used to work with. She was one
of a group of us who went to lunch each day in the work canteen. One
lunchtime, when she was about half-way through her lunch, she pulled a large
flask out of her bag and proceeded to tip the uneaten dinner into the
flask - a sort of vacuum flask doggy-bag. One of my colleagues gave her a
look with spoke volumes - "WTF are you doing" - because she put her pud in
with her main course :-(

She explained that she sometimes got hungry in the middle of the afternoon
and her blood sugar got low, so she saved some of her lunch to eat later on.
Excellent idea, but the idea of mixing her pud in with her roast beef and
potatoes was very weird. Prior to this, she'd intrigued some of us by eating
her pud *before* her main course - and my wife and I still use her name
("let's have a Jane-snack") to describe having a dessert (eg some biscuits
or a cake) before the savoury part (sandwiches etc) when we're having a
picnic.