[jofzar]

I really hope we get a video out of this to see how bad it actually is and how much "pressure" is needed for this.

> Incidents/Injuries: Thermos has received 27 reports of consumers who were struck by a stopper that forcefully ejected from these containers upon opening, including complaints of impact and laceration injuries requiring medical attention. Three consumers suffered permanent vision loss after being struck in the eye.

That's an awefully large amount of reports about this. I wonder what about the design makes it a rocket compared to what I would assume is a pretty standard design?

> The Stainless King™ 470ml Vacuum Insulated Food Jar is the ultimate day to day companion to keep your food at optimal temperatures. Keep fruit fresh and vegetables cool for up to 14 hours while you take on the day. For your favourite soups, pastas or stir fry, they’ll stay warm for up to 9 hours – ideal for taking last nights left overs. You can be sure that your food will be perfect for consumption at lunchtime after you pack it in the morning. The wide mouth makes it easy to fill and clean, and comes crowned with a stainless steel lid that doubles as a serving bowl. Plus, it comes with a handy stainless steel spoon that fits neatly into the lid compartment.

It's meant for storing food, for anyone who is confused why someone would be.

[baq]

> I wonder what about the design makes it a rocket compared to what I would assume is a pretty standard design?

Injuries nonwithstanding, the quality of the seal means it was an exceptionally well designed item for the purpose of storing 99% water.

side note: there's a reason you get a visit from the FBI if you buy ten pressure cookers (e.g. if you find a great Black Friday deal and have a large family and plan Christmas gifts...)

[data-ottawa]

I’ve exhausted the branches of my imagination, what is the danger of 10 pressure cookers?

[Hobadee]

You can make bombs out of pressure cookers. Since they are so good at holding pressure, you seal off the over-pressure release valves and then pressurize them until they burst (usually via some stupid or illegal means to begin with) then when they burst there is a ton of excess pressure. Big pressure = big boom.

[ReptileMan]

They are exactly as good as any other pot made of 18/10 steel with similar thickness. Other vessels like propane tanks are much better.

Boston marathon worked because - well pressure cookers at the time didn't draw much attention to them.

[walrus01]

But if you're not working with cutting torches and welding equipment, there's no easy way to open a propane tank enough to put an explosive in it (assuming purely amateur equipment) and then seal it up again good enough to hold high pressure. A pressure cooker on the other hand is ready made to have a big opening to put lots of stuff inside and then seal it up again.

[walrus01]

there's tons of material online from religious radical groups on how to turn one into an IED

[shepherdjerred]

e.g https://en.wikipedia.org/wiki/Inspire_(magazine)

[RattlesnakeJake]

"Make A Bomb In The Kitchen Of Your Mom" sounds like the beginning of a teenager's bad joke

[baq]

under no circumstances should you google the anarchist's cookbook

[masfuerte]

They make great bombs.

[malfist]

Find me a news story about a person who got a visit from the FBI after buying 10 pressure cookers.

That beggars the imagination. You think the FBI is monitoring the sales of every restaurant supply store?

[Litost]

Here's a story in the Guardian about a women who was visited by local police in New York after her family searched for pressure cookers and backpacks.

https://www.theguardian.com/world/2013/aug/01/new-york-polic...

Though it turns out the truth might be more complicated and it may have been her husbands employer triggering the search, not the FBI? https://www.darkreading.com/cyber-risk/pressure-cooker-flap-...

[2muchcoffeeman]

The pressure build up can be quite a lot from fermentation. I’ve accidentally fermented drinks in glass swing top bottles. And upon attempting to open the bottle the pressure ripped the stopper and the metal parts right off the bottle at high speed.

If you were purposely fermenting something, you could build enough pressure to pop the bottle.

[christophilus]

Yep. I once had half a bottle of kefir end up all over my kitchen ceiling. After that, I always opened them outside, pointing away from anyone.

[lioeters]

> half a bottle of kefir

I also found this the hard way, once you open a bottle of kefir or yogurt and then close it again to drink/eat later, the fermentation process speeds up due to the additional oxygen, building up pressure until you open it the next time. Fortunately no one got hurt.

[thedougd]

I'm guessing pressure is not allowed to escape before it's on the last thread.

[x______________]

Found a comical video of the situation which required no intervention from the user[0].

Needless to say, storing food in a thermos as advertised is different than coffee is hot and should have been foreseen by the team who supervised the approval of "Oh we need more sales.. Oh right, let's double down on our market and tell customers to put food in their Thermoses!"

[0] https://m.youtube.com/watch?v=rTQ6c-_QYW4

[numpad0]

Thermos jars have interior threads for an inner plug and an exterior thread(singular) for the cosmetic cap that doubles as a drinking cup. Maybe there's a condition where the external cup would be holding the inner plug from releasing, and then upon removing the cap, the entire lip starts tapering outward and lets go of the plug without gradually relieving pressure.

(to be fair, I don't think an externally threaded cap will solve this problem. If the thread held to a higher pressure, then the core part of the plug will eventually blow out even more energetically. An overpressure vent port is still necessary)

[kevin_thibedeau]

All they need is a section of threading that gets looser to release pressure while it is still retained in the top.

[malfist]

Thats all? What happens if the jar is turned upside down in this case? What if something is set on the lid? What if the jar is with someone heading to a camp site in a 4 wheeler and it is vibrated a lot?

[kevin_thibedeau]

You have a section of threads that seal or have a gasket. This is simpler than a relief valve that can leak or collect bacteria.

[malfist]

The cap is rigid. Either the threads constrain movement or they don't. A section of threads that allow for movement would still find the overall system constrained by other threading.

[kevin_thibedeau]

The pitch stays the same. The simplest way is tapered threading with a sufficiently deep groove to retain when only the first few threads are engaged. Less simple is a custom male profile that transitions into a squared ACME like profile to let gas leak by.