I made my powder tonight and took pictures along the way. First, let me say that along with other processes discussed on this site, making your own black powder has its own set of risks and hazards all of which should be well understood and mitigated should you decide to do it. Also, make sure that if you decide to do it, you are in compliance with any laws that may apply. Lastly, I have read all the posts on this thread about the dangers of this process and why we shouldnt be doing it, I especially am entertained by those that counsel against it because of how dangerous it is....so is melting lead. If you dont think this should be done then dont do it. I am posting this because I think its neat, it makes me feel a little connection with those that have gone before me and paved the way for our 'hobby' (which was their necessity), and I like to know how things worked. If you are wondering if I am qualified to do this, dont worry about it, I am an adult and can take care of myself. I wont post about how qualified I am.
Last but not least, I have fired this powder in my .50 cal TC black diamond with great results, next year I intend to kill a deer with powder I made and a bullet I cast.
The ratio is 15:3:2 Of KNO3, Charcoal, and Sulfur respectively. I make batches using (in grams) 150g KNO3, 30g charcoal, and 20g sulfur. You must make your own charcoal out of willow, grass, or another very soft wood or it wont work well. I make my own out of willow, grind the charcoal in a hand crank old fashioned meat grinder, then screen it to sift out the chunks, and use only the fine product for the process. To learn how to make your own charcoal, google it.
You will also need some 90+% isopropyl alcohol, chilled in the freezer (i put it in the night before), 750ml is fine, and I use the whole bottle.
I buy my other ingredients on line from a pyrotechnic supply co, get the finest grade you can.
1. Measure your amounts and screen/sift the charcoal and sulfur together to keep it fluffy.
2. Bring about three cups of water to boil on stove, stir in 150g KNO3. Keep stirring and make sure all the KNO3 is dissolved, dont overwater the mix as it will be harder to reprecipitate later. Turn off heat.
3. Slowly sift in the charcoal and sulfur mix. It will float on top of the water so wisk it in or stir vigorously until you have a grayish sludge.
4. Once the sludge is fully mixed and wetted, remove it from the stove and pour in the chilled alcohol while stirring.
5. Keep stirring until the sludge is cool. I actually will put the pan in an ice bath to bring the temp down to ice water temp. What this does is causes the KNO3 to precipitate out of solution onto the charcoal and sulfur particles allowing for intimate oxidizer/fuel apposition. You will see the previously watery mix begin to thicken as the precipitation occurs.
6. Once you are confident all the KNO3 has precipitated out (its been ice cold for about 5-10 min), you can begin to carefully pour it through a coffee filter supprted by a screen strainer.
7. Let the liquid filter out, it takes a while and I usually have to do two filters worth as they fill up quick. I also scoop and pour into the filter to reduce mess.
8. After most of the liquid exits via gravity, bunch up the filter, wrap another filter around it and begin to slowly squeeze out excess liquid until you have a compacted ball of powder. This you can set on a wad of paper towels until ready for use.
9. It is necessary to get as much liquid out as you can prior to corning, if excess remains it will mud up when pushed through a mesh and not grain up properly. Once you have a nice ball, grate it through a screen onto a large pan lined with paper for drying. Allow this to dry over night, undisturbed, away from flame, where a kitty cat wont find it!!!!
Meet your new black powder. I store it in cleaned out tupperware or used powder cans that seal well. I have used some in my .50 cal that was a year old successfully. You can put a packet of rice in to absorb moisture and dont store too much in one container. Test it, play with it, have fun. Remember, you are responsible for your own actions not me (or anyone else for that matter). I post this only in the spirit of sharing something that I made that I found to be quite enjoyable so do your homework and be safe.
Again, for those that have poo poo'd making black powder, dont do it then. BTW, the batch I just made cost me about 50 cents.