Vacuum flasks (OTish)

[Chris Holford]

A few years ago I had had a great day chasing free flight model planes at Old Warden and was pretty tired... To rive me a bit for the drive home I reached for my flask of hot coffee....-and it slipped from my oily grasp and there was a tinkling sound as the coffee ran out of the broken glass liner. :( From that day on I've used stainless steel flasks. But, I have a luking suspicion that they tend to lose their effectiveness after a year or so. They don't seem to keep things as hot as they did when new. Could it be that the vacuum is gradually lost over a period of time? I'm thinking of trying a traditional glass flask again. What has been your experience with stainless flasks?

[Davey]

I have a couple of American Stanley SS flasks, which have always been brilliant. I last used one of them a few months ago, and it seemed as good as I remember it from years ago. Still piping hot after several hours.

[Andrew Gabriel]

"Thermos - meaning hot, unless you drop it."

- Flanders and Swan.

I assumed they would just have a molded foam liner, made from something like celotex, but a web search does call them vacuum flasks.

[S Viemeister]

[Chris Hogg]

AIUI stainless steel is a better heat conductor than glass anyway, so the contents of the flask would cool faster in a SS thermos than in a glass one. I see no reason why the vacuum should fail though.

[polygonum]

Agreed. Although taking longer than a year for any appreciable difference. However, when we replaced a couple of small ones something like two years ago, they were very much less expensive, seemed more effective, and have suffered no deterioration we can detect.

I would not revert to glass even if they might be marginally more effective. The loss of the contents at a time that you probably really wanted that drink is one reason. Another is the difficulty of keeping them clean around the rubber seal. All too many end up with something between the glass and the metal/plastic outer.

[Brian Gaff]

I don't know but its about time the techies sorted out glass. I can remember this issue from right back when I was at school, and I'm 64 now. I simply cannot believe that technology has not made flasks better. With metal ones they do tend to cool very fast. I'm not even sure they actually have a vacuum. The conduction is the issue. What about making them out of plastic and instead of a vacuum, use some of that material Shuttle tiles were made of. Brian

[DerbyBorn]

Perhaps the OP has got one that is for keeping cold drinks cold and not hot drinks hot!

[Tim+]

Not hard to clean if you disassemble them.

Tim

[GB]

It depends on make, but a genuine thermos flask can be unscrewed and cleaned, with care.

[GB]

Do you want boiling hot coffee? If I'm after a quick pick-me-up, I prefer it cool enough to drink down quickly. I add cold water to my thermos.

[Bob Eager]

They're probably more expensive! :-)

I tend to be able to drink really hot drinks....long story but when you're staying in a barracks and they give you ten minutes for breakfast...my brothers are the same!

[spuorgelgoog]

I have found that by preheating with boiling water, then filling with hot freshly made tea, the tea is still drinkably-warm (but not hot) at the end of an 8.5 hour shift.

I don't know if they have a vacuum or are foam insulated; I assume the latter. And I don't know how old mine is as I didn't get it new.

Owain

[Tim Watts]

Yes. I have a plastic bodied one and I unscrew the bottom, and drop the base, case, thermos unit, rubber seal and 2 lids in the dishwasher.

Gets everything nice and clean after using for food.

If it's only tea/coffee I don't bother and just rinse it whole.

[Chris French]

We have a few here, can't say I've noticed any drop in performance generally, so certainly if it has happened it's not noticeable.

However, we had one that failed, so much so that the outside gets noticeable warm, though couldn't actually see any fault with it. At least 8 years old I think

Yup.

Eldest daughter is in Air Cadets, they were at the Remembrance parade last year. Someone had a big flask of Hot Choc for them for afterwards, whilst they were assembling up there the flask (glass) took a dive.....

[Bill]

I have a SS flask from Argos, make unknown, that has lasted for years, coffee is still hot enough to drink after 24hrs. It finally succumbed to a 10' drop that put a larger than normal dent in it and now has a warm spot around the dent. My thoughts had been, over the years, to cut it open when it finally failed and see how it was constructed. This thread has re-awakened the idea, so when time allows I will be getting the angle grinder out!

[Mr Pounder]

Did free flight many years ago. Then I got fed up with chasing and losing them and used single channel. Same difference really. Dunno about your flask :-)

[Dave Liquorice]

You pre-make the coffee, yuk. it stews, even instant.

I only carry hot water in a flask(*) and pre-heat the flask with a mug of boiling water sloshed about inside, poured out then filled with boiling water.

(*) Glass one, steel ones just don't keep things hot enoough, long enough.

[Dave Liquorice]

Er, you just take them apart and clean 'em.

[Davey]

You don't have the right SS flask, then.