Making black powder at home

[Ian]

I've been fooling with the Kraft paper charcoal all this year, finally concluded after pyrolyzing multiple batches and using several different varieties that it's decent but not great. Soft fouling, but a good bit of it. Virgin fiber Kraft dunnage puts out a surprising amount of shiny black stuff that condenses on the outside of the retort like creosote. The heavily recycled stuff with little specks of beer carton ink still in it did better with both power and cleanliness, surprising to me.

Jake at everythingblackpowder on utoob just put out a comprehensive, updated how-to video a couple weeks ago and it gave me a lot of food for thought about my whole process, so I started refining it. I also did some research into Cottonelle toilet paper and discovered a few things that might explain why it works so well for him. Anyway, I installed temperature probes in my retort and cooked down four rolls of Cottonelle tonight with extremely good results, much better than the Charmin I pictured a few posts above. I think controlling the temperature exactly to between 550 and 600F is critical to getting good fuel. Next I delved into my corning process again and discovered that since I switched jacks on my press (the original started leaking badly), now my puck densities are coming out around 1.9 g/cc, plus or minus a few hundredths, which might explain the slow and dirty results paper has been giving me. I'm going to refine that too by making a new piston for my die which bottoms out at a certain point and then weigh my meal and work out exactly what it takes to get to 1.75 g/cc and see what that gives me in final, granulated density in a measure at 3Fg granulation. Hopefully I'll hit the weight/volume balance and also keep my density consistent from puck to puck and thus make a cartridge-worthy powder.

The other thing that needs improvement is my ball mill. I've been doing pretty well with an old airsoft BB jar filled 1/3 with lead-filled .45 ACP cases but they're starting to shuck the lead and the jar cracked on the last run. Fortunately I always seal the jar in a ziplock before packing it into a folded towel in my STM brass tumbler so the meal didn't leak out and find sparks in the brushes of the little drive motor. After searching for days I finally found a good container for the ball mill in the form of a 1.6 gallon Curtec storage container, but it will have to be ordered from Holland. In the meantime I'll make one from 6" PVC drain pipe like everyone else, probably glue some lifter strips inside, and pack it in the STM drum like I had been doing. I'll need to make a bunch more media slugs too, this time with less lead in them so I can make a more effective crimp on the case mouth. I'm not spending hundreds of dollars on brass ball bearings just for this.

I'll also make a puck-cracking die to simplify that process and try to make a dusting drum of some sort to help deal with the excess dust I keep getting from my powder.

The grinding and classifying processes I'm using now are working well so no upgrades needed there. Everything except the press has been moved out to my new shed and I have a spot outside facing ten acres of nothing important so I'll probably go ahead and put the ball mill in a little bunker and start milling more like a pound of meal at a time. Once I get a good formula and process fine-tuned and tested thoroughly I'll make up a few pounds of charcoal and blend it all into one big batch, do the same with the green meal, then I can pull from the stockpile and press pucks at my leisure and break/grind what I need once they're dry and have consistent powder every time.

Right now a lot depends on how well the Cottonelle works. The willow has been leafing out for a couple of weeks now so I need to find out quickly if I need to go cut a bunch of fresh, 1" shoots to stockpile or just buy a bunch more TP.

 

[creosote]

Jake mentioned stitching to brass ball bearings. I figured they'd be spendy.

 

[RBHarter]

I know this is obvious but lead doesn't spark ....... It's not like there's not a .440-.510 mould laying around maybe a few rejected balls .........

 

[Ian]

I know this is obvious but lead doesn't spark ....... It's not like there's not a .440-.510 mould laying around maybe a few rejected balls .........

That's what I started with, .600" balls cast from "hard" lead alloy. Lead balls work but they cause issues with lead dust contamination as they wear and aren't as efficient as brass due to the softer surfaces. The contamination makes for much more fouling in the barrel and harder to remove fouling. Solid brass balls aren't as efficient as they could be due to lower mass. Lead-filled brass cartridge cases are my "best of both worlds" solution to both problems, plus the cylinders seem to mill better than spheres in my experience, at least in the tumbler and loading rates/speed I have been using.

 

[RBHarter]

I might still have a couple pieces of brass rod laying around 1/2×12" I think. I had some silly idea about turning about 06' sized cases with 30-30 capacity.

 

[fiver]

i don't think that's a silly idea at all.

mine was the silly one.
i was gonna open the case necks and push brass tube down in the cases in smaller incremental diameters.

 

[Ian]

I think Col. Harrison did that tube thing too. I made a couple filled with hard lead alloy up to the base of the neck and drilled them out, but then I discovered the miracle of Hodgdon Titegroup and never looked back.

 

[Missionary]

What about Zinc Balls... An old Lee ball mold and zinc wheel weights seem to abound.

 

[Ian]

What about Zinc Balls... An old Lee ball mold and zinc wheel weights seem to abound.

That is a capitol idea! I'll look into it.

 

[300BLK]

molten zinc and aluminum moulds might not play well together

 

[fiver]

you could leave the sprue plate open for this purpose.

 

[Ian]

you could leave the sprue plate open for this purpose.

Or just remove it. Vise grips and band saws make short work of attached sprues.

 

[Ian]

Last night I overhauled the drive roller on my Rebel 17 tumbler because a bearing was going out and the rubber was starting to shred and squirm around on the shaft. FYI, rather than buy a new pulley shaft from Rebel, I did some measuring and ordered a sack of 3/4 o.d. by 3/8 i.d. by 1" long rubber spacers and installed them on the 12mm shaft using high_proof alcohol as a non-damaging lubricant. The fit was perfect and resulting, stretched o.d. of the rubber was identical to the original so I know that's the right size.

After cleaning and tuning up the tumbler base I cut a 10" section of 6" schedule 40 PVC pipe, cut a 3/4" plywood disc, and glued it in one end with Christie's PVC cement. I'll drill countersinks and put screws in it for mechanical support but It shouldn't leak. A 6" rubber cap and hose clamp covers the other end and makes a lid. I may need to glue strips of PVC or hardwood inside for lifting the balls and powder. I found a couple of large wet-liner O-rings from a heavy truck engine and used them to bush the PVC tumbler jar in the Rebel's drum after removing the rubber liner insert. All this works out because with the slightly larger motor pulley I made a while back to improve belt life, the drum runs at 71 RPM and that just so happens to be the ideal ball milling speed for a 6" i.d. jar with half inch media, plus it simplifies my jar construction by just fitting an insert into the drum I already use. This should be far better than the 4" airsoft BB jar packed in a towel that I had been using. All ready try out now except for media.

The last thing I did last night was turn a piston limiting ring for my pucking die. With some basic math I was able to work out a system that gives me pucks pressed to exactly 1.7 g/cc density every time and is dead simple to use. I weigh 28.4 grams lightly dampened meal on a creased Manila card, funnel it directly into the die, insert the piston, stop, and pusher, and press to the stop. I let it sit under pressure while weighing the next charge, pop out my puck, and repeat. Tonight I ran a batch of 77/13/10 Kraft meal that had been milled for 24 hours previously and got this neat stack which totaled out to 1.705 g/cc with 5mL of water added and a pinch of loss through small crumbs. I want to see if my previous over-pressing of this Kraft paper powder is why it wasn't great.

 

[Missionary]

Well that sounds like a good fix.
Here in southern Peru mechanics come up with very interesting repairs using applications of whatever they have on hand.

 

[Ian]

I tried out three paper powders that I made over the past couple of weeks, and they were all lame. Moving backwards.

Kibler SMR, .445 ball .018" patch, Hoppe's 9+ lube, 50 grains by volume of 3F for all tests.

Kraft paper @ 75/15/10 ratio, milled 24 hours in my old tumbler setup, pressed to 1.9 g/cc averaged 1276 fps.

Same Craft paper char @ 77/13/10, pressed to 1.7 g/cc averaged 1201 fps. No surprise there as it was only 41 grains to the 50 grain measure.

Finally, Cottonelle @77/13/10, averaged 1401 fps and made a HUGE cloud of cocoa-brown smoke, never seen anything like it. Single-digit SD so that's good, but it isn't burning well. This was milled in my makeshift mill jar which is a soft HDPE gallon container with a couple of wooden paddles installed. It made a "whump, whump, whump" noise indicating slamming the mix around but not much grinding going on. I think it is under-milled.

In the past I used recycled Kraft paper at 75/15/10 that I thought was over-cooked, milled it 12 hours and got 1515 fps or so using the same milling setup that I used to make good, mid-16s powder with black willow charcoal. It's going to take a lot to get to 1800 fps that Jake is getting with Cottonelle. I may be dealing with a combination of under-milled and under-cooked charcoal since I've been very careful not to over-cook the TP. It's black through and through but not glossy, grey, and shrunken to the degree that overcooked paper tends to be.

I'll cast up some more media tonight and get another batch of Cottonelle going in my new PVC jar.

 

[Missionary]

I am enjoying reading this lab work. No telling how much time and $$ you are saving others who are looking to make their own at home one day.

 

[fiver]

brown powder was a thing for about 6 months, then smokeless over shadowed it.
Rye grass was the base material.

i only bring it up since straw [from wheat] is usually available in miniature [like 5lb.] bales come October time.
unless you want me to mail you a 50lb'er...

 

[Ian]

I read about the brown powder once, I think they skipped on the sulphur too on account of not needing it for ignition purposes in cartridges.

Making black powder comes down to three big challenges: Making good charcoal, milling all the ingredients together well enough, and pressing it well and accurately enough. Getting ingredients, grinding, and classifying are all gravy.

Charcoal comes down to what source material works best...or well enough and cooking it at the right temperature (generally 550-600F). Lots of good woods to use ranging from cedar and fir to black willow, cottonwood, and as I discovered even chinaberry. Jake found out that Cottonelle ultra comfort TP makes powder as good as alder buckthorn and maybe even cleaner, so that's what I'm sticking with for a while unless I just can't make it work. We have lots of black willow here and it makes good powder, it's just that the fouling is harder than any of the paper-based powders I've made so I'd like to stick with paper if I can.

Milling, that's the thing that kicks everyone's butt. You can't just go out and buy a ball mill suitable for it. You have to build from scratch or modify stuff. The easiest thing probably is what I did in the beginning after graduating from the toy rubber rock tumblers: Use a Rebel 17 high-speed rig and pack a smaller, hard, airtight jar inside the tumbler drum with towels. Fill 1/3 with brass media, fill up to half with ingredients and mill for 24 hours. I'm trying to go up to a 6" ID hard jar with the Rebel and even with 150 .45ACP cases filled with lead in it it only filled 1/4 of the way up so it doesn't roll continuously inside even after correcting the RPM for a 6" drum with a custom motor pulley. Belts last longer though with the larger motor pulley. So you have to play with stuff to get efficient milling. I'm going to add another 75 or so cases and see if it will still run, the drum is getting heavy. If that doesn't work I'll probably drop back to a 4" jar using SCH-40 PVC and pack it with towels again, that will be easier than modifying the tumbler any further and I can still use it for tumbling cartridge brass without too much of a changeover.

Pressing pucks, I got that part nailed....but not without a lathe and 20-ton shop press. The only thing that has me puzzled is getting back to the proper granulated density. I just can't get my powder to weigh what the volume measure is set to without pressing it to nearly the theoretical maximum, and pressing that densely slows it down and makes it dirty. GOEX supposedly presses the meal down to 1.7 g/cc, but when I do that my powder is 18% lighter. At least I can make clean, weak powder that might be more desirable for my big thumper cartridge rifle so my retinas stay glued down. More experimentation will tell.

 

[Missionary]

Good morning
Can the local humidity % be a factor during the pressing operation ?
I know it does interesting things to baking bread down here where humidity can be from 10% during the dry months to 90% during the wet months.

 

[Ian]

Yes, humidity is a huge factor. If ambient humidity is high, it is necessary to dry the oxidizer and charcoal (separately) in an oven before milling or the meal clumps up. I usually dampen the meal right after getting it out of the mill but sometimes it takes more water than others to make it just right for pressing.