Black Powder Manufacture - Questions page
From PyroGuide
This page is a supplement to Black Powder Manufacture, a place where popular questions and possible objections are discussed in a nonchalant manner.
If you have additional questions or objections to the things said about BP manufacture - including your own experiences - please use the discussion pages at interim. Frequently asked questions will then be included here.
- Regarding raw materials:
"Where do I get cheap potassium nitrate?"
Potassium nitrate is a chemical best bought in bulk quantities. KNO3 is used as a fertilizer in agriculture. Most fertilizer grade KNO3 comes in 50 lb. bags, is very cheap (usually costs about or less than a dollar per kilogram) and is plenty pure. Some products however show purities ranging near the 90% and should be avoided even for BP manufacture; you just don´t know what´s in the rest. Some suitable brands are e.g.: Champion (USA), Yara Krista-K Plus (>99,5% pure) (Europe & Australia) and Haifa Multi-K (Australia). In general the purity of fertilizer KNO3 isn´t given on the bags however MSDSs containing purity information can generally be obtained from the supplier or the manufacturer's website; just don´t be confused by the N-P-K values which in case of KNO3 are about 13,5-0-46, independent from the materials purity. You best avoid buying from pharmacies or chemical suppliers, their prices often are ridiculously high.
"Will using charcoal from grill briquettes end in a fast powder?"
No. They are made from various kinds of hard wood and contain binders (e.g. clay) and other matters. Briquettes recycle the dust left from charcoal making/packing and are designed to burn very long; all characteristics not welcome when it comes to fast powder.
"What kinds of charcoal will give a fast powder?"
See the Charcoal Suitability Table where different kinds of charcoal are discussed. Of course you will also have to choose a suitable method of manufacture (e.g. willow charcoal will not end in fast powder when poorly integrated). Note that the commonly stated hardwood-softwood rule (softwood is good for BP etc.) is no reliable distinction, as there are a lot of hardwood charcoals which give superior results e.g. alder buckthorn (see Lancaster on Charcoal).
"Where do I get high performance charcoal from?"
The best and cheapest way is to make your own but you can also watch out for individuals who sell homemade charcoal. Some pyro suppliers sell good charcoal but many others only source hardwood airfloat. Remember that only 15% by weight of charcoal are required for BP manufacture, so you will be able to make a reasonable quantity of BP with a few kilograms of charcoal (probably an argument pro buying charcoal). However one of the main requirements for BP is consistency, so you wanna use the same high-quality charcoal each time and if you make your charcoal yourself you certainly know what you have got. So if you have legal access to suitable kinds of wood you should learn how to cook charcoal. But please do not chop park trees etc.
"Is stump remover pure enough source of KNO3 for black powder?"
Yes, most stump remover is in the 98%+ purity range, which is plenty pure for black powder. Though I am told Grant's stump remover is slightly impure. Do not get Bonide Stump remover; it is not made from Potassium nitrate, but rather Sodium metabisulfite.
"How can I purify KNO3?"
KNO3 can be dissolved into hot or cold water and then filtered to remove any insoluble matter. As long as most of the impurities are insoluble, you will be left with 99.x% KNO3.
- Regarding things stated about BP manufacture:
"You said that BP made via hand grinding is performing weakly but I obtained a fast powder this way!"
I said that the force of the end product remains weak under all practically defensible circumstances. If you use a good charcoal and grind a small amount like hell you may get rewarded with a bite of fast powder. I hope you do not plan making shells or similar things, otherwise it ends like this: "Come on mum, please grind on. It´s just a pound."
