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Please don't keep us in suspense OP. Did you get it open? 
Weird issue with vacuum flask
- Thread starter bazzabear
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Soldato
he's burnt the house down.Please don't keep us in suspense OP. Did you get it open?
Caporegime
Or heated up too much and exploded like a grenade with food splattered all over the walls.
Sorry guys. I tried the heating, and it seemed to make a bit of difference. Problem is that it also makes the flask hard to handle, because it is both too hot to hold, and very slippy because it's wet.
So I'm ashamed to say I gave up. Basically, there was little point in getting it open at this point because we wouldn't trust it to not do the same again in future anyway.
It's a shame, because it had actually done a pretty good job of retaining temperature in the food so far - keeping it hot enough to eat by lunch time. But you can see in the pictures the design fault - the threads are just stamped in to the metal, and are very shallow so easily overcome.
So I'm ashamed to say I gave up. Basically, there was little point in getting it open at this point because we wouldn't trust it to not do the same again in future anyway.
It's a shame, because it had actually done a pretty good job of retaining temperature in the food so far - keeping it hot enough to eat by lunch time. But you can see in the pictures the design fault - the threads are just stamped in to the metal, and are very shallow so easily overcome.
Soldato
Have you got anything like a vice clamp or a workmate? You could do with clamping the small plastic cap end of the flask so that it is upside down then try and muscle the main / body part of the flask.
Soldato
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wait, if you couldn't get it open because the food had cooled how did you know it was still warm?
Schrodinger's soup.
Normally Raymond steps in and answers these questions for me.
But: Because it's not the first time we've ever used the flask.
Tried using some G-clamps on each end of it to get a better grip. But they couldn't grip well enough without bending the flask wall.
Daughters backpack is going to be quite heavy with the new setup.
- flask
- campingaz
- stove
- 2 g clamps
- water
- pan
Soldato
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Caporegime
I would have thought sitting it in a bowl of hot water long enough (say an hour) would bring the internal temp back up to original temp, it's like you are doing sous vide with it. Then wipe dry and open.
You don't need to open it when wet, there would be lots of time before it cooled again.
You don't need to open it when wet, there would be lots of time before it cooled again.
Soldato
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Normally Raymond steps in and answers these questions for me.
But: Because it's not the first time we've ever used the flask.
damnit, was hoping the answer would be more fun than that.....
Permabanned
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You should have recorded all your attempts and put it up on youtube tbh.
Soldato
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If it's insulated and took several hours to cool enough to create an unbreakable vacuum, would it not also take that long to heat up the internals enough to reverse that vacuum?
Also, hot water cools very rapidly - Just ask my cup of coffee.... So you'd need to immerse the flask in water on a rolling boil for a period. Crack out the family-sized pasta pan!
Are you proposing to buy an even bigger flask, fill it with water, put this flask in, then leave it several hours?
Soldato
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just make sure the bigger flask is good quality and wont have this vacuum issue, because there's only so many times you can do this before you run into problems like now your kids lunchbox is bigger than your house.
Soldato
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Were my words not small enough for you?
Caporegime
The difference is when you lose the heat, the internal has a starting temp but it is not constantly kept warm with another heat source.
You are now putting it in a fixed (say 95c) water tank and keep it at 95c, so the time to heat it back up again would be less.
Soldato
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Ah - You didn't specify fixed. I just presumed the bowl had hot water poured into it from a kettle or something, whereupon it'd start cooling rather unhelpfully... which is why I suggested what you pretty much just confirmed!
TL;DR - Yeah, what you said... which is what I said... but not what she said.