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Bot0nist
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I once saw a mythbuster's show where they made a "rocket" with a steel pipe filled with solid paraffin and cored. N<sub>2</sub>O was
injected through the core and ignited at the nozzle by pyrogen (cellulose nitrate I think). It failed to achieve lift but made a lot of noise. Once
again, Jamie and Adam where embarrassingly hokey, as per usual.
NOTE: I am thinking about trying to do some tests with wax and KNO<sub>3</sub>. I was thinking in an old 50ml beaker as a "barrel", as
Endimion17 put it. I will make a composition of pure paraffin candle wax and finely divided potassium nitrate with a small percentage of sulfur to
hopefully lower ignition temperatures. (I will burn under proper ventilation to avoid the slight H<sub>2</sub>S risk) I will try my best
to make the composition stoichiometrically optimal. For mixing I was thinking of slightly dissolving the paraffin in kerosene and making a slurry with
the oxidizer and sulfur. I would then try and evaporate off the volatile kerosene while thoroughly mixing. But in the end I may have to melt the mix
with a boiling water bath and pour into the beaker. For ignition, I was thinking a candle wick would be perfect. I'll try and have something up by
this weekend. I have everything on hand. Just gotta get to it.
Does anyone have any suggestions for my little planned experiment. I'm still in the contemplative/brainstorming phase.
[Edited on 24-1-2012 by Bot0nist]
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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Neil
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You really need something for the nitrate to bite, something that can serve as a fuel and withstand being heated to the point where the nitrate starts
to oxidize, perhaps adding some starch or just a bit of sugar?
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Bot0nist
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Ok, I'll try one with powdered sugar proportion, and one with lamp black. I thought the sulfur may help in this aspect.
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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Fusionfire
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What was I thinking, *facepalm*. Of course, but less sensitive without the sulphur.
Sorry I am learning a foreign language ATM and my chemistry thinking cap is dusty 
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Fusionfire
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Quote: Originally posted by Neil  | | You really need something for the nitrate to bite, something that can serve as a fuel and withstand being heated to the point where the nitrate starts
to oxidize, perhaps adding some starch or just a bit of sugar? |
What about magnesium powder?
Let the KNO3 + wax be the bulk of the redox reaction, but the Mg powder would serve as hot spot nucleation sites.
Sadly I don't think the more common/cheaper aluminum powder would work, unless it is prepared in an anaerobic ball mill, because of the very strong
oxide layer.
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Bot0nist
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3 small scale attempts tonight. All fail. Working in sub gram scale though. Will try variations on sugar, sulfur, carbon, and maybe pyro-Al (German
blackhead, 5 micron) if it comes to it, in a larger scale this week.. I just feel that wax as the primary fuel wont work. It's too hard to ignite,
even when melted together with a lot of or sulfur or carbon. This wiki excerpt doesn't give me much hope. Maybe when I make the 50-100 ml in a beaker
and try to burn it as a normal candle I will get a reaction after some time, if things heat up enough. I'm having doubts though.
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Paraffin wax (C25H52) is an excellent material to store heat, having a specific heat capacity of 2.14–2.9 J g−1 K−1 (joule per gram
kelvin) and a heat of fusion of 200–220 J g−1.[10] This property is exploited in modified drywall for home building material: it is infused in
the drywall during manufacture so that, when installed, it melts during the day, absorbing heat, and solidifies again at night, releasing the
heat.[11] Paraffin wax phase change cooling coupled with retractable radiators was used to cool the electronics of the Lunar Rover.[12]
~wiki
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U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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Neil
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| Quote: Originally posted by Fusionfire | | Quote: Originally posted by Neil | | You really need something for the nitrate to bite, something that can serve as a fuel and withstand being heated to the point where the nitrate starts
to oxidize, perhaps adding some starch or just a bit of sugar? |
What about magnesium powder?
Let the KNO3 + wax be the bulk of the redox reaction, but the Mg powder would serve as hot spot nucleation sites.
Sadly I don't think the more common/cheaper aluminum powder would work, unless it is prepared in an anaerobic ball mill, because of the very strong
oxide layer. |
The oxide layer gets fluxed by Potassium oxide and is actually broken as the Al heats and expands in the flame front.
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Fusionfire
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| Quote: Originally posted by Neil | | Quote: Originally posted by Fusionfire | | Quote: Originally posted by Neil | | You really need something for the nitrate to bite, something that can serve as a fuel and withstand being heated to the point where the nitrate starts
to oxidize, perhaps adding some starch or just a bit of sugar? |
What about magnesium powder?
Let the KNO3 + wax be the bulk of the redox reaction, but the Mg powder would serve as hot spot nucleation sites.
Sadly I don't think the more common/cheaper aluminum powder would work, unless it is prepared in an anaerobic ball mill, because of the very strong
oxide layer. |
The oxide layer gets fluxed by Potassium oxide and is actually broken as the Al heats and expands in the flame front. |
Yeah but the problem is initiating the reaction in the first place.
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