Self Heating Rocket Fuel

[TimO]

I've seen self heating cans before, but this is the first time I've seen one in my local Sainsburys, and unusually the Rocket Fuel branded, extra caffeinated stuff.

I've bought some, in the spirit of investigation.  I imagine it could be ideal for things like night rides, although on a FNRttC, it may be difficult to find the right time when I've got long enough to start it heating, and then drink it without burning myself!

Apparently they also do a Hot Chocolate version, but they didn't have that in my Sainsburys, which is a shame, since it would probably be more palatable than White Coffee (based on instance coffee and hot chocolate from machines).

[Valiant]

Is it any good?

[TimO]

I haven't tried it yet.  I may take one up with me to the start of the FNRttC tomorrow, so I've got something to drink whilst waiting for the off.

[TimO]

I tried a can out at the start of the FNRttC on Friday (not surprisingly!), and it was a bit of a downfall.  It was slightly above tepid.  I drank it anyway, since caffeinated fluid is caffeinated fluid, and always good for a night ride, but wasn't that impressed.

I thought I may have insufficiently shook it, so tried the second can at home, with some very vigorous shaking, and it was slightly below tolerably warm.  I've had colder cups of coffee, but only ones that I made, and have then forgotten to drink for half an hour.

Not very successful at all.  Either both of mine were faulty, or the heating system is woefully underpowered.

Frankly, it didn't taste that good either.  Most cups of coffee I've had from machines have tasted better, and machine coffee is normally pretty rank stuff.

Not recommended.

[Valiant]

Ah what a shame!

[dasmoth]

In any case, I'd rather assumed you'd have access to real rocket fuel.  My understanding is that some types are indeed "self heating"  .

[spesh]

In any case, I'd rather assumed you'd have access to real rocket fuel.  My understanding is that some types are indeed "self heating"  .

Anyone for a hypercaffeinated energy drink called Devil's Venom?  It wouldn't be much less lethal than the real thing. 

[TimO]

Anyone for a hypercaffeinated energy drink called Devil's Venom?  It wouldn't be much less lethal than the real thing. 

Hydrazine is pretty horrible stuff at the best of times.  I know that when they're fueling a satellite up at Kourou (ESAs main launch site), the local fire brigade stand around outside, and the people doing the fueling are wearing fuel proof protective suits.  Very unpleasant stuff to be around, and as the article briefly mentions, depending on the type, it can spontaneously ignite in contact with the appropriate catalyst (typically integrated into the rocket engine itself), and that's aside from being highly toxic even when it's not burning.

It does make an excellent fuel though!

[TimO]

Did you manage to get the temperature above tepid?  I wondered if extreme vigour with the shaking would help?

[TimO]

I found that the bottom, heaty thing, isn't very well sealed and once the reaction starts white foam leaks out. Combined with vigorous shaking, this can lead to a white polka dot pattern on everything in the vicinity  ...

That's odd, I didn't get any leakage from the heating unit, and I'd be surprised if there was, since it's probably quite a toxic material, and you wouldn't want to handle it.  You certainly wouldn't want to ingest any.

From a green and/or recycling perspective, it's really not very good, since the chemicals are going to make it no-go for recycling the materials, and the complicated mixture of plastics and metals would probably make that impractically complex anyway.

[dasmoth]

Did you manage to get the temperature above tepid?  I wondered if extreme vigour with the shaking would help?

Maybe that's the secret of Liberty: the fearsome vibration of a big solid motor helps to get the most out of the upper stage!

[Biggsy]

Does the initial temperature have anything to do with it?

[TimO]

Both of mine started off moderately warm, since that's the sort of temperature that ambient has been recently.

Neither of mine showed any signs of leaking, and I did attempt to shake the second one somewhat vigorously (the first one less so, since I followed the instructions).

Having a quick look around, Calcium oxide is sometimes used in these devices, and whilst not toxic as such, because it reacts very aggressively with water, contact with eyes, the respiratory tract etc is quite hazardous.  Anhydrous calcium chloride is also used, and since it's actually used as a food additive, it clearly isn't toxic, but again can be hazardous because of the potential for burns.

So, it seems that the constituents of the self heating element of the can aren't likely to be dangerous, providing they have fully reacted with the water.  If any part hasn't fully reacted with water, then it could be hazardous.