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Author: Subject: Parafin wax at 70:1 potassium nitrate?
Scudroe
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[*] posted on 9-1-2017 at 07:24
Parafin wax at 70:1 potassium nitrate?


Just wondering if anyone here has recently attempted to make a paraffin wax based solid fuel rocket motor?

I had a little trouble believing my own initial calculations coming out at ~70:1 oxidizer: fuel ratio?

I'm planning on a starting mix of KN03 and sugar as usual to attempt to reach ignition of the paraffin wax / KN03 mix.

If it gets anywhere near working there will be other developments.

I won't be doing this for a while, btw (need to fix shed, don't mix in kitchen) so may be sporadic in appearances here.
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PirateDocBrown
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[*] posted on 9-1-2017 at 07:46


Let's see, 4 moles of KNO3 @ 101g each will produce 10 moles of O atoms, which will react with 5 moles CH2, at 14 grams each.

4x101 = 404 grams KNO3 for each 5x14 = 70 grams paraffin. 5.77:1, more or less.
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Bert
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9-1-2017 at 08:26
Scudroe
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[*] posted on 9-1-2017 at 08:28


Thanks for the fast response.

Looks a hell of a lot more likely than mine.
But not:

15 (O) + 5 (CH2) -> 5 (CO2) + 5 (H2O) ?

Putting it around 8:1?

The 70:1 I came up with first time out was obviously waaayyy off (and thanks, it matters, have not seen successful examples of this mix to date).

[Will update towards the end of the year on tests].
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PirateDocBrown
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[*] posted on 9-1-2017 at 13:49


You are much more likely to get CO than CO2.
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Scudroe
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[*] posted on 10-1-2017 at 01:12


Thanks, makes sense

Will post results in < 12 months for anyone interested.
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Σldritch
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[*] posted on 11-1-2017 at 11:51


From my experience of potassium nitrate you want fuels that are not very volatile such as sugar or carbon and not glycerol or stearin both of which i have tried myself.

Stearin gives a nice flame though if mixed with potassium nitrate and sugar ;) (Granulated stearin)
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PHILOU Zrealone
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[*] posted on 11-1-2017 at 14:35


KClO3 (potassium chlorate)/candle wax is also worth a try, need a slight boost to start like sugar/chlorate initiator and some carbon...you need incandescent C to start it.
Then it burns fiercely, bright and generates a lot of white fumes.

I have made candle wax fumigens with that.
KNO3 will be unsuitable for such a pyro comp because way harder to initiate than KClO3 and much lower production of oxygen...




PH Z (PHILOU Zrealone)

"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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