Sciencemadness Discussion Board - Black powder without KNO3 and S?

Black powder without KNO3 and S?

testimento - 6-12-2013 at 14:48

Ok so I am in need of black powder for use as a propellant material that has compatible pressure increase for projectile ejection purposes. The major problem with me lies with the composition for the powder.

I have no potassium salts available, unless in very expensive or complicated ways, but sodium, calcium and ammonium salts are, though. Also I have no access to elemental sulfur whatsoever.

I searched through some sources and they cited that a very slightly less powerful black powder can be made from 80:20 KNO3:C composition. The sodium and calcium salts downfall is with the moisture, but this shouldn't be a major problem for my purpose because the propellant material is to be sealed in plastic/metal container. Sodium black powder is referred to have very high initial pressure peak, so it is used in quarrying rather than propellant. Calcium black powder I have no sources, and ammonium salts, by my knowledge, tend to be the far end of the rapid pressurization of composition pyrotechnics and therefore usually not recommended.

So, is it possible to make a compatible substitute from a sodium or calcium nitrate based compositions for black powder propellant?

Metacelsus - 6-12-2013 at 16:56

I made black powder using NaNO3 instead of KNO3 (same molar quantity). It performs similarly to usual black powder. However, it is quite hygroscopic and produces an intense yellow flame.

DubaiAmateurRocketry - 6-12-2013 at 17:10

For burn rate, potassium nitrate works one of the best in black powder compositions out of other nitrates. However if you really cant purchase potassium nitrate, even in fertilizer form, then you could try perchlorates, such as potassium or ammonium perchlorate. those salts have a good pressure-burn rate curve that burns fast enough for good projectile''ejection'' speed

testimento - 7-12-2013 at 11:00

Calcium nitrate is of my particular interest. The formula next to KNO3 (101g vs 164g) dictates that I should be able to use about 61 grams of it for every 100 grams of KNO3 to get same outcome, and much more importantly, it is easily available. From this I counted that I could use 5 moles of calcium nitrate with 16.6 moles of carbon powder (approx. 800g of Ca + 200g of C) to get ideal performance.

How is table sugar as a regulator instead of sulfur? It is used in fuse mixtures and I thought it could perhaps work aside?

How would sodium perchlorate, carbon powder and 0-x% of sugar work?

hyfalcon - 7-12-2013 at 12:35

Mr. Sleeter has forgotten more about this subject than we will have to time to learn.

http://lib.freescienceengineering.org/view.php?id=215727

hyfalcon - 7-12-2013 at 15:47

The picture is right but that download is NOT the book I have. Missing about 150 pages and I don't even recognize the 19 pages in this download. Still good info though.

Bert - 7-12-2013 at 19:53

If you can't find Sulfur in any country on earth, you are not trying.

Assuming you have anhydrous nitrates, the physical form of your nitrate/carbon based propellants likely matter more for the shape of the pressure curve than the particular nitrate you choose. Ammonium nitrate will have the highest specific impulse, as the reaction products are virtually all gas.

DubaiAmateurRocketry - 7-12-2013 at 20:09

Ammonium nitrate does not burn well at all without metal powders and have really one of the slowest burn rates, if you want to use black powder which is meant to burn really fast. perchlorate usually have higher burn rate than nitrates, and potassium's salts have high burn rates. calcium nitrate is very hygroscopic and usually comes in hydrated form, unusable. You can purchase oxidizers such as KNO3 very easily from local fertillizer shops, I bought 10 Kg of cheap KNO3 few years ago in fertillizer mart and it have 98% purity, enough for pyrotechnics, and I still have half of it left.

Bert - 7-12-2013 at 20:52

For that matter, conversion of calcium nitrate to potassium nitrate is trivial-

Trotsky - 10-12-2013 at 00:21

Convert the calcium nitrate to potassium nitrate.

You can give CaNO3 a shot of You can get it nearly anhydrous. Good luck there. Ammonium nitrate is a terrible choice. It burns like shit. I've tried VERY hard to get it to work, because as he it's said above, it should have a very high isp, but it just doesn't work.

Zyklon-A - 10-12-2013 at 16:22

Quote: Originally posted by Bert

For that matter, conversion of calcium nitrate to potassium nitrate is trivial-

Yes, but he said that he does not have any potassium salts at all.

Zyklon-A - 10-12-2013 at 16:37

If you have CaNO3 you can make flash powders that burn much faster than BP.
CaNO3+Al is hard to ignite, try CaNO3+MG, not sure about the ratios, sorry, try twice as much CaNO3 as Mg.
I would try myself, but I don't have any CaNO3 right now

[Edited on 11-12-2013 by Zyklonb]

Bert - 10-12-2013 at 16:57

Quote: Originally posted by Zyklonb

Quote: Originally posted by Bert

For that matter, conversion of calcium nitrate to potassium nitrate is trivial-

Yes, but he said that he does not have any potassium salts at all.

The only reason one would not have access to Potassium salts useable to convert Calcium nitrate to Potassium nitrate would be that one was in prison or in orbit.

Potassium chloride and/or Potassium carbonate are available anywhere in the world.

Sodium free salt substitute. Water softener salt. For gods sake, anyone with some water and wood ash has access to all the potassium carbonate available that they would care to extract.

Similar to the claim that he can't get Sulfur, the only thing standing in the way would be ignorance or lazyness.

Zyklon-A - 10-12-2013 at 17:07

Keep in mind it was him who said that he did not have any K-salts, not me, I should have thought of wood ashes though.
True about sulfur for sure, I can get sulfur at a gardening shop, $10 for 5lbs, and I've heard that that's expensive even.

[Edited on 11-12-2013 by Zyklonb]

Zyklon-A - 10-12-2013 at 17:10

Quote: Originally posted by Bert

Quote: Originally posted by Zyklonb

Quote: Originally posted by Bert

For that matter, conversion of calcium nitrate to potassium nitrate is trivial-

Yes, but he said that he does not have any potassium salts at all.

I'll bet that one could even get potassium salts in prison, not sure about space though.

Vikascoder - 13-12-2013 at 19:25

If you can't access potassium salts and sulfur then u could use sodium nitrate and sugar and charcoal it also gives a good thrust

Zyklon-A - 14-12-2013 at 09:26

It still would not burn as fast as BP.
I just got some CaNO3, so I will try CaNO3+Mg.

Vikascoder - 14-12-2013 at 21:47

Quote: Originally posted by Zyklonb

It still would not burn as fast as BP.
I just got some CaNO3, so I will try CaNO3+Mg.

If you have sodium nitrate and magnesium and u r interested in making flash powder then use sodium nitrate instead of calcium nitrate because sodium nitrate will give u much better results

Zyklon-A - 15-12-2013 at 13:42

Would NaNO3 work better than KNO3,
Because I have a lot of KNO3.
I just got CaNO3 to try and see if it works, not because I didn't have KNO3, or NaNO3.

DubaiAmateurRocketry - 15-12-2013 at 14:10

Quote: Originally posted by Zyklonb

Would NaNO3 work better than KNO3,
Because I have a lot of KNO3.
I just got CaNO3 to try and see if it works, not because I didn't have KNO3, or NaNO3.

Depends what are you using it for.

In general, KNO3 is the most prefered, it actually ''burns'' with some fuels, for other nitrates, you would need much more heating and sometime extinguishing without continuous heating. Such as Sodium/ammonium nitrate.

Zyklon-A - 15-12-2013 at 14:15

Good, I have like 3 lbs of KNO3, just made a ball mill for Al powder.

DubaiAmateurRocketry - 15-12-2013 at 14:48

Quote: Originally posted by Zyklonb

Good, I have like 3 lbs of KNO3, just made a ball mill for Al powder.

Al powder ? are you doing it with KNO3 ? Aluminum powder have a very high temperature of activation to burn or make flash powder, due to its oxide layer protection and its high boiling point.

Zyklon-A - 15-12-2013 at 19:38

I know,when I'm using Al powder, I add a pinch of sulfur, it lowers the activation temperature considerably, I can light it with a glowing splint.

DubaiAmateurRocketry - 16-12-2013 at 00:01

Quote: Originally posted by Zyklonb

I know,when I'm using Al powder, I add a pinch of sulfur, it lowers the activation temperature considerably, I can light it with a glowing splint.

I think I tried that before however it burned much worse than using magnesium or titanium.

Pulverulescent - 16-12-2013 at 09:42

Quote:

Ammonium nitrate is a terrible choice. It burns like shit. I've tried VERY hard to get it to work, because as he it's said above, it should have a very high isp, but it just doesn't work.

It will work with a sufficiently strong ignitor . . .

Zyklon-A - 16-12-2013 at 09:47

What ratios did you use?
It worked fine for me, if the powder is very fine it works well, ignition isn't to hard, if you add a little sulfur, and it still burns quite fast.