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Ooh a titanium fire - that would be really cool to see. I wonder if it's possible to make titanium thermite as easily as aluminum thermite?

AndrewBissell 7y ago
The titanium fire could be fun but the problem is you don't want to be anywhere near that hydrazine when it goes. https://www.latimes.com/business/la-fi-spacex-crew-dragon-escape-system-fuel-20190423-story.html https://www.latimes.com/business/la-fi-spacex-crew-dragon-es...
- CaliforniaKarl 7y ago
  For a 'fun' watch, check out NASA's "Toxic Propellant Hazards" video, from ~1966. https://www.youtube.com/watch?v=Zha9DyS-PPA https://www.youtube.com/watch?v=Zha9DyS-PPA
  - kevin_thibedeau 7y ago
    4:46: Let me just move this beaker of rocket fuel over a foot while I aim a syringe of oxidizer.
    - bch 7y ago
      * applies oxidizer with a Zorro flourish
    - zaroth 7y ago
      I love these videos. But to be fair, wouldn't the quantity of oxidizer be the limiting factor?
CaliforniaKarl 7y ago
> titanium (a technically flammable metal similar to magnesium) Yeah, it didn't click with me immediately. I saw "titanium fire" but my brain substituted "magnesium fire". The idea that titanium can catch on fire in a similar way, is…concerning. … and of course there's a small-scale YouTube video: https://www.youtube.com/watch?v=cH76ObzYIxc https://www.youtube.com/watch?v=cH76ObzYIxc
- RaceWon 7y ago
  > "titanium fire" but my brain substituted "magnesium fire". Ditto.
- xkcd-sucks 7y ago
  Eh all metals like to burn, which is why so many are found as oxides in nature. For example, a "thermobaric lance" used to punch holes through reinforced walls is just a bunch of iron metal burning in excess oxygen, the colors in fireworks are diverse metals, etc. It's an example of "kinetically driven" versus "thermodynamically driven" in that metals all want to burn and give off tons of heat, but in everyday human circumstances the ambient temperature is cold enough to prevent the metaphorical ball from rolling down the hill. It's rather surprising that any metals at all can withstand the remarkably unhappy oxidizers used in modern rocket fuels! Probably the metal part in contact is an oxide layer that's easily abraded by big chunks of crap.
  - FreeFull 7y ago
    Gold is very resistant to any sort of oxidation (the oxides are less stable than the metal), but of course using gold for a rocket wouldn't be very practical.
    - andrewflnr 7y ago
      That's why we need to bring down that giant gold asteroid! Gold fuel tanks for everyone!
- RyJones 7y ago
  I've used titanium shavings, lit by high explosives, to start fires. Search youtube for "boomershoot fireball" and look for the earlier ones
jandrewrogers 7y ago
Most metals can be used to successfully make thermite when paired with appropriate metal oxides. It is a very simple thermodynamics equation that determines which combos work well. The main considerations are the net energy release of the reaction, which can vary widely, and the amount of energy required to bootstrap the reaction, which can be extremely high. Classic thermite -- aluminum and iron oxide -- is a middling combo but has the large benefits of being dirt cheap and low density. Designing exotic thermites is a literal direct application of the elementary reaction thermodynamics that you learn in basic chemistry classes. Bootstrapping ignition is a bit more involved and often multi-stage.
- DonHopkins 7y ago
  The article says: "Rather, the cause lies in a more exotic and unanticipated chemical/material interaction between a plumbing valve, liquid oxidizer, and a helium-based pressurization system." How can chemical interactions be "exotic"? Or did they mean "exothermic" or "exciting" or "esoteric"? Is "exotic" a technical term, or did the chemicals simply come from a distant foreign country, and how does that affect their physical properties? https://www.quora.com/What-are-exotic-compounds-in-chemistry https://www.quora.com/What-are-exotic-compounds-in-chemistry Is there such a thing as non-baryonic titanium? https://en.wikipedia.org/wiki/Exotic_matter https://en.wikipedia.org/wiki/Exotic_matter >Hypothetical particles and states of matter that have "exotic" physical properties that would violate known laws of physics, such as a particle having a negative mass. I can understand why you'd want to fill a rocket with exotic matter of negative mass: to make it lighter! ;)
  - asark 7y ago
    I'd take it to mean "not supposed to be there; from outside (the place where the reaction happened)". Webster's 1913 for "exotic" includes: extraneous. Same source for "extraneous" includes: without or beyond a thing; not essential or intrinsic; foreign.
  - jandrewrogers 7y ago
    The term "exotic" in a chemistry context means one of two things. First, it can mean observed chemistry that is seen neither in nature nor the lab under ordinary conditions. In other words, it is theoretically possible but the required conditions are so atypical that the expected probability of it occurring unintentionally are very small. I'm guessing this is the case that applies here. Second, "exotic" can mean engineered chemistry that is far outside the standard industrial spectrum, typically because there is a unique application with very special requirements. Industrial chemistry is all about price performance of the chemistry not absolute performance, but some use cases are more performance sensitive than price sensitive so people will design bespoke and unusual ("exotic") chemistry for the purpose. It is a curve. Everyone uses the cheapest chemistry that still does the job adequately.
nine_k 7y ago
IIRC, titanium fires were a problem during the development of SR-71, too.
lutorm 7y ago
When you ignite metals in the presence of pure oxidizer, though, the result is not so much a "fire" as an explosion. It doesn't really "look" different than any other explosion...
- Gibbon1 7y ago
  I read some of the early experiments with termite reactions involved heating crucibles filled with metal oxides and aluminum power in a furnace. Results were surprising as they were unfortunate.
throw20102010 7y ago
I haven't tried it, but I would make a somewhat educated guess to say, no. Not that it can't be done, but that it probably isn't as easy to get the reaction going as regular thermite. Thermite made from aluminum and iron can start with a child's firework sparkler, so it is pretty easy to make and use. Titanium, while not a noble metal, is more resistant to heat and corrosion than aluminum and is just generally less reactive. You might call it "less un-noble" than aluminum. I expect that you'd have a much harder time getting thermite started using titanium. Just look at how much it took to get the titanium fire going on the Crew Dragon- a chunk of NTO had to slam into a valve at really high speed. Edit: Since you piqued my curiosity, I decided to see if it had been done before. It has: http://developing-your-web-presence.blogspot.com/2008/10/on-titanium-thermite-bronze-age-and.html http://developing-your-web-presence.blogspot.com/2008/10/on-... You replace iron oxide with titanium oxide (since titanium pieces oxidize only on a thin outer layer I expect you would need a very fine mesh), and keep the aluminum. This seems to need a little work but it has been done.
- jandrewrogers 7y ago
  Thermite reactions only happen at extremely high temperatures. Your intuition based on room temperature chemistry is incorrect. Sparklers (i.e. the fireworks) sometimes use titanium to make the sparks, but the primary thing you are igniting is a conventional oxidizer salt (nitrates) and an organic binder. Basically weak rocket fuel with some particles of flammable metal in it to throw off sparks. This is not a thermite reaction. The surface areas of the metals have a huge impact on practical flammability, hence why fine powders are easy to ignite. Iron is also quite flammable as a fine powder but I don't expect my skillet to spontaneously combust on my stove.
  - benj111 7y ago
    I think you're misreading the parent. They're implying you can start the reaction with a sparkler, not that the sparkler reaction is the same.
    - jandrewrogers 7y ago
Gibbon1 7y ago
I obtained back you could just order this stuff, 100g of titanium powder. Toss a teaspoon on a camp fire and it makes pretty silver sparks.

AndrewBissell 7y ago

The titanium fire could be fun but the problem is you don't want to be anywhere near that hydrazine when it goes. https://www.latimes.com/business/la-fi-spacex-crew-dragon-escape-system-fuel-20190423-story.html https://www.latimes.com/business/la-fi-spacex-crew-dragon-es...

CaliforniaKarl 7y ago
For a 'fun' watch, check out NASA's "Toxic Propellant Hazards" video, from ~1966. https://www.youtube.com/watch?v=Zha9DyS-PPA https://www.youtube.com/watch?v=Zha9DyS-PPA
- kevin_thibedeau 7y ago
  4:46: Let me just move this beaker of rocket fuel over a foot while I aim a syringe of oxidizer.
  - bch 7y ago
    * applies oxidizer with a Zorro flourish
  - zaroth 7y ago
    I love these videos. But to be fair, wouldn't the quantity of oxidizer be the limiting factor?

CaliforniaKarl 7y ago

> titanium (a technically flammable metal similar to magnesium) Yeah, it didn't click with me immediately. I saw "titanium fire" but my brain substituted "magnesium fire". The idea that titanium can catch on fire in a similar way, is…concerning. … and of course there's a small-scale YouTube video: https://www.youtube.com/watch?v=cH76ObzYIxc https://www.youtube.com/watch?v=cH76ObzYIxc

RaceWon 7y ago
> "titanium fire" but my brain substituted "magnesium fire". Ditto.
xkcd-sucks 7y ago
Eh all metals like to burn, which is why so many are found as oxides in nature. For example, a "thermobaric lance" used to punch holes through reinforced walls is just a bunch of iron metal burning in excess oxygen, the colors in fireworks are diverse metals, etc. It's an example of "kinetically driven" versus "thermodynamically driven" in that metals all want to burn and give off tons of heat, but in everyday human circumstances the ambient temperature is cold enough to prevent the metaphorical ball from rolling down the hill. It's rather surprising that any metals at all can withstand the remarkably unhappy oxidizers used in modern rocket fuels! Probably the metal part in contact is an oxide layer that's easily abraded by big chunks of crap.
- FreeFull 7y ago
  Gold is very resistant to any sort of oxidation (the oxides are less stable than the metal), but of course using gold for a rocket wouldn't be very practical.
  - andrewflnr 7y ago
    That's why we need to bring down that giant gold asteroid! Gold fuel tanks for everyone!
RyJones 7y ago
I've used titanium shavings, lit by high explosives, to start fires. Search youtube for "boomershoot fireball" and look for the earlier ones

jandrewrogers 7y ago

Most metals can be used to successfully make thermite when paired with appropriate metal oxides. It is a very simple thermodynamics equation that determines which combos work well. The main considerations are the net energy release of the reaction, which can vary widely, and the amount of energy required to bootstrap the reaction, which can be extremely high. Classic thermite -- aluminum and iron oxide -- is a middling combo but has the large benefits of being dirt cheap and low density. Designing exotic thermites is a literal direct application of the elementary reaction thermodynamics that you learn in basic chemistry classes. Bootstrapping ignition is a bit more involved and often multi-stage.

DonHopkins 7y ago
The article says: "Rather, the cause lies in a more exotic and unanticipated chemical/material interaction between a plumbing valve, liquid oxidizer, and a helium-based pressurization system." How can chemical interactions be "exotic"? Or did they mean "exothermic" or "exciting" or "esoteric"? Is "exotic" a technical term, or did the chemicals simply come from a distant foreign country, and how does that affect their physical properties? https://www.quora.com/What-are-exotic-compounds-in-chemistry https://www.quora.com/What-are-exotic-compounds-in-chemistry Is there such a thing as non-baryonic titanium? https://en.wikipedia.org/wiki/Exotic_matter https://en.wikipedia.org/wiki/Exotic_matter >Hypothetical particles and states of matter that have "exotic" physical properties that would violate known laws of physics, such as a particle having a negative mass. I can understand why you'd want to fill a rocket with exotic matter of negative mass: to make it lighter! ;)
- asark 7y ago
  I'd take it to mean "not supposed to be there; from outside (the place where the reaction happened)". Webster's 1913 for "exotic" includes: extraneous. Same source for "extraneous" includes: without or beyond a thing; not essential or intrinsic; foreign.
- jandrewrogers 7y ago
  The term "exotic" in a chemistry context means one of two things. First, it can mean observed chemistry that is seen neither in nature nor the lab under ordinary conditions. In other words, it is theoretically possible but the required conditions are so atypical that the expected probability of it occurring unintentionally are very small. I'm guessing this is the case that applies here. Second, "exotic" can mean engineered chemistry that is far outside the standard industrial spectrum, typically because there is a unique application with very special requirements. Industrial chemistry is all about price performance of the chemistry not absolute performance, but some use cases are more performance sensitive than price sensitive so people will design bespoke and unusual ("exotic") chemistry for the purpose. It is a curve. Everyone uses the cheapest chemistry that still does the job adequately.

nine_k 7y ago

IIRC, titanium fires were a problem during the development of SR-71, too.

lutorm 7y ago

When you ignite metals in the presence of pure oxidizer, though, the result is not so much a "fire" as an explosion. It doesn't really "look" different than any other explosion...

Gibbon1 7y ago
I read some of the early experiments with termite reactions involved heating crucibles filled with metal oxides and aluminum power in a furnace. Results were surprising as they were unfortunate.

throw20102010 7y ago

I haven't tried it, but I would make a somewhat educated guess to say, no. Not that it can't be done, but that it probably isn't as easy to get the reaction going as regular thermite. Thermite made from aluminum and iron can start with a child's firework sparkler, so it is pretty easy to make and use. Titanium, while not a noble metal, is more resistant to heat and corrosion than aluminum and is just generally less reactive. You might call it "less un-noble" than aluminum. I expect that you'd have a much harder time getting thermite started using titanium. Just look at how much it took to get the titanium fire going on the Crew Dragon- a chunk of NTO had to slam into a valve at really high speed. Edit: Since you piqued my curiosity, I decided to see if it had been done before. It has: http://developing-your-web-presence.blogspot.com/2008/10/on-titanium-thermite-bronze-age-and.html http://developing-your-web-presence.blogspot.com/2008/10/on-... You replace iron oxide with titanium oxide (since titanium pieces oxidize only on a thin outer layer I expect you would need a very fine mesh), and keep the aluminum. This seems to need a little work but it has been done.

jandrewrogers 7y ago
Thermite reactions only happen at extremely high temperatures. Your intuition based on room temperature chemistry is incorrect. Sparklers (i.e. the fireworks) sometimes use titanium to make the sparks, but the primary thing you are igniting is a conventional oxidizer salt (nitrates) and an organic binder. Basically weak rocket fuel with some particles of flammable metal in it to throw off sparks. This is not a thermite reaction. The surface areas of the metals have a huge impact on practical flammability, hence why fine powders are easy to ignite. Iron is also quite flammable as a fine powder but I don't expect my skillet to spontaneously combust on my stove.
- benj111 7y ago
  I think you're misreading the parent. They're implying you can start the reaction with a sparkler, not that the sparkler reaction is the same.
  - jandrewrogers 7y ago

Gibbon1 7y ago

I obtained back you could just order this stuff, 100g of titanium powder. Toss a teaspoon on a camp fire and it makes pretty silver sparks.