Sifted black powder

[johnnypyro]

Hello from the UK!

 

Thanks to all the contributors to this forum, past and present, for the goldmine of information.

 

I am making BP for lift and burst sifting each component of a 75:15:10 composition with 100 mesh. I do this three times, mixing in a closed plastic box between sifting. I add 2.5% dextrin, 25/75 isopropyl alcohol/water and grate through 10 mesh. Once dry I separate what passes10 mesh but not 20 mesh (4FA equivalent?) as my BP. The charcoal I use is good quality willow.

 

The result is good, but not very hot.

 

I'm curious to know if there is anything more I can do to improve this BP, or is the next step a ball mill?

 

 

[Arthur]

The best powder is always good ingredients, well milled, pressed and corned then size graded for different purposes. Short the process get poor powder. If there was a better way people would use it.

[Arthur]

Go to Royal Gun Powder Mills at Waltham Abbey, See how powder was made when it was a military and mining necessity. Look on their WWW for the books they publish.

[Uarbor]

I would say it's time to move on to a ball mill. I started off with a rock tumbler then I ended up getting a spare set of jars for the rock tumbler then I built a set up where I can turn all four jars at once but basically it's still a rock tumbler. Skylighter has an excellent tutorial on how to optimize a rock tumbler to the correct speed for Milling. Here is what my powder looks like after 3 hours in the Tumbler. The charcoal is Willow, weeping willow to be specific.

Edited June 22, 2022 by Uarbor

[johnnypyro]

Thanks for all the help, especially @Arthur

 

For the newbies, like me, here's a video comparing the sifted powder green powder, made as above, with ball milled black powder (3-component, ceramic media, 4 hours) and exactly the same precursors and manufacturing.

 

https://youtu.be/YENzFsAIL1Q

 

Bottom is the green powder.

Edited July 7, 2022 by johnnypyro

[justvisiting]

While it's true that ball-milling black powder as a complete mixture makes good black powder, it's also true that single component milling can produce near-identical results. This has been proven empirically, and there has been no proof offered to the contrary. The allegation that good black powder can't be made without milling all 3 components together is a fondly held false belief. I have experimented extensively with this concept and been able to somewhat erode that belief in the eyes of some

 

In North America, we have much more room to safely locate mills for black powder. 3 component milling is easy, so that's the way most people do it. In places like Europe where people live closer together, it's more difficult to mill a potentially explosive mixture without endangering others. That's where single component milling is an ideal alternative.

 

The most important thing to do with single component milling is to reduce the particle size of the charcoal. Folks think of 'airfloat' as fine charcoal. It's actually a blend of particle sizes, some quite coarse. Well-milled charcoal does not easily scatter in the air like 'airfloat' does. In airfloat charcoal, the cells are not all broken down, so the material is very light due to the gas in the cells. I mill my charcoal with stainless steel media rather than lead. Lead wears VERY rapidly if milling charcoal alone. Lead is perfectly suited to 3 component milling though, and is the best choice for that- also empirically proven. It doesn't make the best powder by a great margin, as some might suggest. I refer to the milling of my charcoal as 'super-milling', since I mill it for a long time, 4-6 hours. Also, I use a type of charcoal that is suited to making black powder, like willow, sumac, or Eastern Red Cedar (a juniper).

 

I've made screen-mixed black powder using a 100 mesh screen as well. Best to start when you're young 3X would take forever! I found that with well-milled charcoal, 2X through 40 mesh with mixing by hand in between is sufficient, and WAY faster.

 

IF screen-mixed powder can satisfy the requirements (and I say it can), it's a good alternative for those that don't prefer the easier but potentially very dangerous way. Most older pyros will (correctly) say that it's an unnecessary use of resources to make the hottest black powder in many cases. So, whether or not screen-mixed black powder is just as powerful as the hottest ball-milled powder becomes a moot point in general. I'd put my screen-mixed powders up against milled powders any day. I use screen-mixed powder for nozzleless rockets, lift, and burst. Screen-granulated powders are faster, but pucked, corned and graded powders are what I used for testing.

 

Of course, it's necessary to start with fine sulfur (like rubbermakers) and milled potassium nitrate if you want to make screen-mixed powder.

 

I know I said "I" a lot here, and mean no offense. I just feel that it's important to relay that my approach to black powder goes against the norm and it's through actual personal experimentation that I come to the conclusions I have. In many cases, information about black powder is culled from literature about commercial methods, which differ from amateur methods considerably. The notable difference is that commercial black powder is milled in a damp state by a smearing action, and ball-milled powder is milled bone dry by impacts.

 

Writeups of the experiments that were done to form the above conclusions were posted on Pyrobin but that site is now down, maybe permanently this time. I'm happy to share the files with anybody that's interested, or if anybody has any suggestions on where I might upload 4 or 5 articles so that I might be able to link to them.

 

Note: I have ball-milled complete black powder mixtures with stainless steel media for testing purposes, but otherwise would never do it. Stainless steel is practically the best, most versatile media for milling all pyro chems- except complete BP mixes, because it could spark.

[50AE]

Yes, you need FINEST milled ingredients to make black powder to work. It is most easily accomplished via ball mill. If milling nitrate/and sulfur alone, at some point the nitrate will start caking. Caking inside the drum is a good indicator it is fine enough. Caking is recognized when you start hearing your media dry-milling. When scratched between your fingers, the milled nitrate should feel like silk fabric.

Fine enough charcoal will not cake, but becomes creamy and smooth, it flows like liquid.

If mixing components dry, you need to sieve everything through fine mesh due to the nitrate trying to clump. Nitrate clumps give hot melt spots which can be a disadvantage.

Edited July 19, 2022 by 50AE

[SharkWhisperer]

Yes, you need FINEST milled ingredients to make black powder to work. It is most easily accomplished via ball mill. If milling nitrate/and sulfur alone, at some point the nitrate will start caking. Caking inside the drum is a good indicator it is fine enough. Caking is recognized when you start hearing your media dry-milling. When scratched between your fingers, the milled nitrate should feel like silk fabric.

 

Fine enough charcoal will not cake, but becomes creamy and smooth, it flows like liquid.

 

If mixing components dry, you need to sieve everything through fine mesh due to the nitrate trying to clump. Nitrate clumps give hot melt spots which can be a disadvantage.

Caking inside the drum is not a sign that your KNO3 is fine enough. It's a sign that your KNO3 probably had adsorbed a few % of atmospheric water and was clumping because of that. If so, oven dry it for a half-hour or hour and your clumping will disappear completely.

 

Charcoal can cause mill clumping, too, and this is usually the cause of BP clumping in the mill, because charcoal can hold more than just a few % water and still seem "dry" before mixing.

 

If your BP clumps in the mill, ever, it is because one or more of your chems is damp. Clumping is absolutely not an indication that your chems are so very fine. You can spin dry BP in a mill pretty much forever without clumping occurring, ffs. That very inaccurate "advice" needs to be put to sleep finally.

 

If you have clumping issues, you are almost certainly not getting the maximum utility from your chems. And it is very easily prevented.

[50AE]

Good point at first glance and I tried contradicting myself these years ago. I did dry my KNO3 in the oven prior ballmilling it, but it still did cake when fine enough. So I started using this phenomena as reference.

My KNO3 always turned silk-soft fine when it began clumping. It would behave similarly to bentonite.

Although using clumping as a guide could let down someone with genuinely damp nitrate, it never let me down these years of pyro. I would identify the milling coming to an end by listening to the dry knocking of media.

[50AE]

P.S. From another recollection, the purest raw materials I would get, the easiest they would clump. Game changed a lot when I moved from lab grade KNO3 to fertilizer grade. The later seemingly had some anti-clumping agent.

KClO3 would clump even easier when ballmilling. It was electrolyzed, it was washed, double recrystallized grade.

[AZpyroredneck]

I have always used a ball mill for a minimum of 4 hours and never have had a problem with my BP.