Sciencemadness Discussion Board

An $88,000 thermos

Morgan - 5-12-2020 at 15:45

I was watching this video on a thermos kiln and recalled cutting a tall Stanley thermos apart with a hacksaw years ago. There was this black powder between the walls and I assumed it was carbon so the other day I searched to verify that's what it might be and came across this exorbitantly priced repair bill account. It's funny how innocuous items can sometimes surprise you.
DIY Micro Kiln
https://youtube.com/watch?v=Ooabd80A3aQ
So I passed this quirky happening on to the kiln author above. I don't know if there's any dust hazard with today's vacuum thermos bottles but it's maybe something to keep in mind.
https://www.farmshow.com/a_article.php?aid=18232

Fyndium - 6-12-2020 at 04:21

Why it is filled with carbon? Isn't vacuum the better insulator?

unionised - 6-12-2020 at 05:43

They certainly use charcoal in the vacuum space of cryogenic dewar flasks.
The charcoal gets very cold and cold charcoal does a very good job of absorbing gases- so much so that it produces a better vacuum which makes the insulation better.

MidLifeChemist - 6-12-2020 at 07:42

Quote: Originally posted by Morgan  

So I passed this quirky happening on to the kiln author above. I don't know if there's any dust hazard with today's vacuum thermos bottles but it's maybe something to keep in mind.
https://www.farmshow.com/a_article.php?aid=18232


Wow, that is a crazy story! Can't believe that happened

Morgan - 6-12-2020 at 08:23

Here's a glimpse of carbon at step 12.
https://youtu.be/01af9y7PDKk

Morgan - 6-12-2020 at 19:25

A thermos cut in half revealing the carbon.
https://youtube.com/watch?v=WzutESmEJaA

Viewer comment
"What exactly was that insulating material? Or were they smuggling heroin?"

Another thing about sealed vessels, this video reminded me of the time I gelled some guar gum in water with some green dye. It made a slug of material that would slide up and down the glass jar if inverted but if shaken briskly would revert to a syrupy green translucent liquid. Anyway after a few days the firm setting blob effect didn't hang together but stayed a liquid, evolving a great pressure in the jar, which luckily I noticed the bowing lid before something like this probably happened.
https://youtube.com/watch?v=oo5CB3WxGmU

[Edited on 7-12-2020 by Morgan]

Morgan - 24-12-2020 at 16:00

Another thought about the carbon in a hypothetical faulty thermos. If used for this, maybe it'd be possible to go higher than $88,000. Hypothetically, perhaps a poorly welded seam in a Stanley steel thermos could develop a pinhole leak from a sudden cryogenic temperature shock. Then the vacuum would draw in the lox.

"However, the Dewar flasks the LOX was stored in occasionally exploded, which was caused by iron impurities in the activated carbon serving as trace gas absorbent in the insulation vacuum layer in the flask, which caused spontaneous ignition in case of LOX leak into the enclosed space."
https://en.wikipedia.org/wiki/Oxyliquit

[Edited on 25-12-2020 by Morgan]