Slow Sulfurless Black Powder?

I have tried to make some sulfurless black powder by grinding 3 parts sodium nitrate (a potassium nitrate substitute, using this method to make it from ammonium nitrate) and 1 part charcoal (I tested it and it didn't burn good so I added more charcoal (probably making it a 2 KN03:1 C ratio)).  It burns extremely slow (if i laid a pile of the bp that was 1/8 inch wide and 1 inch long it would probably take 5 or more seconds to burn all the way).  I got the charcoal from a burned out bonfire (I don't know what type of wood it was but it wasn't willow or pine), I collected the black chunks that aren't all the way burned out.  I am wondering what the problem is, is it the charcoal or the sodium nitrate? The sodium nitrate is in its purest form, thats what it said here.

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bahi2 years ago

sodium nitrate tends to get moisture very easy. Try using potassium nitrate. Try 70% saltpeter 40% charcoal ( from soft wood, dry straw...) use a not very roasted charcoal, like ancient people did, use "brown" charcoal. And use a ball mill, or if not possible mix it in tiny amounts in a mortar with a pestel and a few drops of water or alcohol. Works better if after that, you granulate the meal (powder from the mortar or mill ball) previously wetted, using a sieve.

bahi bahi2 years ago

Sorry 70% saltpeter 30% charcoal... You can add some powder sugar, 5% of the final weight (make the powder yourself, commercial powder sugar usually has starch)

lemonie4 years ago
Your sodium nitrate may be "crap", but do try grinding your powder wet, as a black-paste, then giving it a good drying-out.

electronicz (author)  lemonie4 years ago
I do wet the powder with alcohol when grinding it and then I let it dry before testing. I am suspicious of the oxidizer because I just made a new batch using the formula 14 KN03: 4 Charcoal: 4 Sugar. The KN03 I used was potassium nitrate
made from ammonium nitrate and potassium chloride, the charcoal I used was charcoal briquettes (the charcoal briquettes are not the purest but it would probably work better than ash), and the sugar was normal granulated sugar. I ground the ingredients separately in a makeshift mortar and pestle for about 5-8 minutes for each ingredient (I wet them with alcohol will grinding), I then mix them together with alcohol and let it dry. The outcome was even worse than the sodium nitrate mix. I will have to try to get some real potassium nitrate and test it out in a new batch.
get some real potassium nitrate - sounds like a good plan, I still think that's probably where your problem is.

electronicz (author)  lemonie4 years ago
Yeah, I will post the results if I get the KN03.