My homemade black powder

[HamGunner]

Burns fairly fast without burn hole traces of unmixed Potassium Nitrate.

Just starting to clump up a bit more on the ends of the barrel, which fell in when I unsealed the lid. Mostly unclumped otherwise and talcum like texture. I really believe it is done or close enough as further milling will likely only cause more clumping.

Edit: Notice that the caking build up on the six sides of the barrel is no longer there or at least not nearly as pronounced as it was two hours prior.

[DoubleBuck]

HamGunner;
Excellent report and let us know when you're able to shoot some of it! It looks good and has that light gray color. I hope it is the best!

[HamGunner]

Well, we have finally gotten our winter weather. Dropped down to 17 right now at right at 10:30 pm and supposed to bottom out into the single digits by morning. Might be a while before I get to actually shoot any of this, but I will have time to finish it up before we get decent shooting weather. I almost went out to dirty up my 1851 yesterday as the temp got up to about 55, but I got side tracked. Saved me some gun cleaning time I guess.

I am hoping I am reading my powder correctly, but it sure looks to be about as milled as my first batches at 20 rpm were after 12 hours of mill time. The sound of the constant cascading of the milling media at 40 rpm surely is an indication that it is working a bunch better than the rhythmic crashing of the media six times per revolution at the slower 20 rpm. The slow speed was perfect for cleaning brass, but I can see it was not what is needed for milling BP.

My last batch was certainly good after 8 hours of mill time, but it did have way more clumping. I did not dry the Potassium Nitrate and it might have contributed to the clumping. This batch appears to have turned out decent enough at 6 hours. Will report back with velocity and grouping when I can shoot some of it.

[maillemaker]

I'm not sure what you guys are calling "clumping".

When I empty my Harbor Freight drum, there are some "flakes", for lack of a better word, that adhere to the face of the cover, for example. Also, when I have emptied the drum of media and all loose powder, I turn the drum upside-down, and I squeeze the rubber drum from various angles. This causes "flakes" of compressed powder to fall out.

But this is just slightly compacted powder, and if you touch it, it turns instantly back to dust.

I mill my green meal for 5 hours. I live in northern Alabama. I don't take any special measures to dry my ingredients before use. However, my ingredients are kept in my shop, which is air conditioned.

[maillemaker]

Burns fairly fast without burn hole traces of unmixed Potassium Nitrate.

Just starting to clump up a bit more on the ends of the barrel, which fell in when I unsealed the lid. Mostly unclumped otherwise and talcum like texture. I really believe it is done or close enough as further milling will likely only cause more clumping.

Edit: Notice that the caking build up on the six sides of the barrel is no longer there or at least not nearly as pronounced as it was two hours prior.

If you touch the caked powder, does it turn to dust?

Steve

[HamGunner]

Yes, it just busts back up into fine dust. This is not Quite as caked or clumped up as my previous batch got, but I milled it I think about 2 hours longer. It made good powder and velocity and density was about the same as my previous batches. I suspect this one will be too.

I am not really concerned much about the caking/clumping, just trying to figure out what actually causes it and perhaps find a way to reduce it. Others have reported major clumping early on in their milling time. I thought perhaps I might play around with my batches a bit and monitor to maybe help throw light on the clumping.

My mill seems to have improved a bunch once I got the tumbling speed up to just over 40 rpm as per Almar's suggestion. At 20 rpm, it took 10-12 hours to get to the point this batch has gotten to in 6 hours. I can tell by the constant and steady sound of cascading media that it must be close to the proper speed and the meal is pulverized into talcum powder a whole lot faster. This batch could very well have been done at 4 hours.

[maillemaker]

Here is what I usually see at the end of 5 hours in my Harbor Freight mill. There is some very fine caking on the walls of the drum and end cap but if you touch it it turns to talcum instantly.

Here you can see some of the flakes that have fallen back into the dust:


Here's what it looks like when I dump it all out:



As soon as I start using a spoon to scoop it into a peanut butter jar it disintegrates into dust like the rest of the green meal.

[Vettepilot]

Oh no, when you get serious clumping, you'll know it. I'm talking about a (usually) single clump so stiff you've got to poke it with something to break it loose/up. Sometimes all at one end of the jar, though if you've got the jar perfectly level, it might have a clump at each end. I use a long screwdriver to break up the clump(s). Once broken up, the powder is super fine and like talc though, and may in fact be done; I don't know.

Virtually everything I've studied about BP over the last several years stresses the importance of extremely thorough milling. That's why I stress about this clumping. I suppose what I need to do is a scientific test. Grab some when it's found clumped, go ahead and process it, and shoot it over a chrono and compare it to known good powder.

What I've been doing is find clumped, bust up, re-fill jar, and repeat. Sometimes three or more times!! And you don't know if it clumped up 2 hours after starting over each time, or two minutes!!

[Vettepilot]

HARBOR FREIGHT MINI-TUMBLER USERS:

So, my mini mill burned up it's motor trying to mill with a jar half full of lead media. (Which is a double overload at 6 pounds +/- BTW.) Replacement motors run about 35 to 40 dollars, and will likely burn up again even if not overloaded according to my research.

The original motor is spec'd at .23 amps and 3000 rpms +/-. I found one three times stronger at .65 amps and the same rpm that I think will fit, and for only 19 bucks. Even if it takes some minor mods to make it fit, I think it will make the handy mini mill much better!

https://www.amazon.com/gp/product/B0...b_b_prod_image

I ordered it, and will let you all know.

(I'm betting it's the exact same motor frame with better windings, in which case it would be a direct bolt on. We'll see....)

Vettepilot

[HamGunner]

This is my green meal after sifting out the media through a #10 screen. It is trying to clump back up slightly as those small clumps seen here are certainly larger than #10 screen.

This leads me to believe that what I thought was minor clumping/caking in the past in the mill was just normal clumping for finished product. It apparently will clump/cake readily once it is completely pulverized into a fine talcum powder consistency.

Since I did not run my mill this time but 6 hours, I apparently did not get as much clumping/caking as I did in my last batch that I milled at the same speed, only the last batch was milled an extra 2 hours for a total of 8 hours.

I was never concerned with this clumping/caking as it did not seem to be severe in my case, but now I am thinking from what I have seen, that I have been milling longer than necessary to get a finished product. Perhaps others that are getting severe clumping/caking are over milling as well.

I did, however, dry my Potassium Nitrate prior to this batch being milled. Perhaps that did help in getting a finished meal in a shorter time period.

[HighUintas]

Is everyone here that is experiencing clumping cooking their charcoal under 600?

I know almar isn't getting clumping, but he cooks his for at least an hour after it gets to temp. I'm wondering if there is something that he is driving off by cooking it longer that others aren't. Then when you cook it to a higher temp, it cooks off this clumping promoting substance much faster so you don't have to hold temp very long.

That's a very complicated theory. Hopefully it's just moisture in the kno3!

[mmb617]

HARBOR FREIGHT MINI-TUMBLER USERS:

So, my mini mill burned up it's motor trying to mill with a jar half full of lead media. (Which is a double overload at 6 pounds +/- BTW.) Replacement motors run about 35 to 40 dollars, and will likely burn up again even if not overloaded according to my research.

The original motor is spec'd at .23 amps and 3000 rpms +/-. I found one three times stronger at .65 amps and the same rpm that I think will fit, and for only 19 bucks. Even if it takes some minor mods to make it fit, I think it will make the handy mini mill much better!

https://www.amazon.com/gp/product/B0...b_b_prod_image

I ordered it, and will let you all know.

(I'm betting it's the exact same motor frame with better windings, in which case it would be a direct bolt on. We'll see....)

Vettepilot

I will be wanting to hear whether this works out or not. I have two of those Harbor Freight tumblers and haven't had any problems with them so far. But at that price if those motors work I'll order a couple just to have them on hand when I do need them.

[Vettepilot]

It's a concerning thing. In this case, I had done several BP testing batches with the mini-mill 1/4 full with no problems. Prior to that it had been used quite a bit for wet tumbling/cleaning brass. Then I decided to "properly" fill it 1/2 full of media, and try it...

I monitored it closely for about an hour; no problems. Then I checked on it about every 20 minutes for another hour; no problems. Then I was about to retire for the evening, have dinner, watch TV, and let it run on it's own for a few hours, and I dam near did so. But at the last second, I thought " No, I'll check on it one more time first." Man!! Am I glad I did so!! I discovered it had stalled, and was literally smoking it was so hot!

While looking for a new motor, I found many complaints of this happening, apparently even when not overloaded as I had done.

The new motor arrived today, (quite fast). If I get a chance, I'll see what fitting it is going to take later today.

Vettepilot

[DoubleBuck]

I just took my double drum Harbor Freight tumbler apart, cleaned and lubed everything, and put larger (7/16) fuel line hoses on the drive and idler shafts. It turned the speed up from 45 RPM's to 62. I'm not going further, until I try it, at this speed. I only use one drum and with a half pound of powder, it only weighs exactly 4 pounds.
The mill is rated at 6 pounds, so I'm hoping cutting that back by a third and increasing the speed by 75% will even out, to close to the same amount of wear. It turns the drum very nicely. I'm not ready to make powder just yet, but soon.
I checked the drive on the motor and it will spin inside the belt, if the drum is stopped, so I don't think it will stop the motor and burn it up, but will watch it as time goes on.

[DoubleBuck]

VettePilot;
On your small mill motor? When I got mine apart, and was really looking things over, I think that a guy could pretty easily direct drive the driving shaft. It already has a milled flat on it, for the pulley set screw. Eliminate the pulley and belt and choose the size of the main shaft you want, to drive the barrel at the proper speed.
Another thing I thought of, while in this little project.
I wonder if anyone has ever tried milling with coins? It doesn't spark, it has sharp edges, is uniform and is various sizes, all reasonably heavy. A half drum of pennies is cheaper than a drum of lead, right now. haha Of course, since 1982, they are a copper mix, over aluminum, but the quarters are mainly copper clad with mixed silver. I think Nickels are still about the same over the years. I know they still weigh five grams. Dimes are like quarters and I have a LOT of pre '82 pennies. I think they are getting close to having a value of nearly three cents each. More than face value, certainly. But, it was just a thought I had. Surely I'm not the first person to think of it. "What do you mill your powder with, Kidder?" "Money, Pilgrim. Money. To get the powder I make, nothing short of money will work. That's the secret, son. That's the secret."

[Linstrum]

Hi guys, something to consider about finely milled powder clumping is that the highly desirable wood creosote in properly cooked charcoal is an oily liquid. I'd bet it contributes to the clumping problem.

Wood creosote is not one single chemical compound, it is a complex mixture of perhaps dozens of distinct chemical entities, some of which are water soluble, and some that aren't. What is in wood creosote depends on the kind of wood, how hot the wood was heated, how long the wood was heated, how much air was present in the container with the wood, and how dry the wood was. A lot of variables are involved in other words. Back in 1972 or 1973, we briefly covered wood creosote in chemistry, but beyond acetic acid, acetone, wood alcohol aka methyl alcohol, benzene, toluene, guaiacol, and a bunch of polyphenols, we didn't go any deeper into it because of all the other possible things that could be in it. By the way, the acetone and wood alcohol are long gone by the time your charcoal is done roasting.

Keep in mind that wood creosote is associated with some kinds of cancer, but I'm not afraid of it. Jeez, how many back yard barbecues and campfires have we all been around! Hey, we even eat the stuff, smoked ham anyone?

I wouldn't worry about how to make charcoal, just as long as your method is very consistent from one batch to the next, and you have found a good wood that has a very low ash content. My cutoff point for ash is no more than 4% when the charcoal is dead burnt, dead burnt meaning the charcoal was heated to dull red heat (950 to 1000 ºF) so there is no creosote. For dark brown charcoal with the optimum amount of creosote, the ash content should be down below 2%. This isn't some magic number, just the very best that Mother Nature has given us to work with. If you want charcoal with 0% ash, use pure white cane sugar to make your charcoal, but it doesn't make very good charcoal because it doesn't have any lignin in it, which is the source of most of the creosote. I've used white sugar charcoal, and it does work, but it takes forever to pulverize because it is hard as coal. Kind of looks like it, too.

The problems with ash are that it dilutes the fuel content, interferes with combustion, and contributes to hard barrel deposits. I already covered how to compensate for fuel dilution by assaying the charcoal and then doing the math to find out how much more charcoal to add. Depending on the kind of wood, it may contain silicon dioxide, which is the same stuff as quartz. When black powder burns, the temperature is high enough to melt silicon dioxide, which in turn reacts with the potassium from the potassium nitrate. There is also carbonate present, and what happens is potassium silicate glass forms. Some of what forms is water soluble, some isn't. What is water soluble is chemically very similar to a material called waterglass, also called sodium silicate. If the amount of ash is very low, then there won't be any problem at all with hard barrel deposit forming.

Well, back to black powder, you guys have done a good job figuring out how to do at home what comes out of some pretty good commercial black powder factories, and found your own wood sources without going to Europe to get it. Just about in your own back yards found your own better wood, too! Awright!

[dondiego]

VettePilot;
On your small mill motor? When I got mine apart, and was really looking things over, I think that a guy could pretty easily direct drive the driving shaft. It already has a milled flat on it, for the pulley set screw. Eliminate the pulley and belt and choose the size of the main shaft you want, to drive the barrel at the proper speed.
Another thing I thought of, while in this little project.
I wonder if anyone has ever tried milling with coins? It doesn't spark, it has sharp edges, is uniform and is various sizes, all reasonably heavy. A half drum of pennies is cheaper than a drum of lead, right now. haha Of course, since 1982, they are a copper mix, over aluminum, but the quarters are mainly copper clad with mixed silver. I think Nickels are still about the same over the years. I know they still weigh five grams. Dimes are like quarters and I have a LOT of pre '82 pennies. I think they are getting close to having a value of nearly three cents each. More than face value, certainly. But, it was just a thought I had. Surely I'm not the first person to think of it. "What do you mill your powder with, Kidder?" "Money, Pilgrim. Money. To get the powder I make, nothing short of money will work. That's the secret, son. That's the secret."

Just an FYI - The new pennies are copper coated zinc and there is no silver in dimes or quarters, that is a nickel wafer.

[mmb617]

It's a concerning thing. In this case, I had done several BP testing batches with the mini-mill 1/4 full with no problems. Prior to that it had been used quite a bit for wet tumbling/cleaning brass. Then I decided to "properly" fill it 1/2 full of media, and try it...

I monitored it closely for about an hour; no problems. Then I checked on it about every 20 minutes for another hour; no problems. Then I was about to retire for the evening, have dinner, watch TV, and let it run on it's own for a few hours, and I dam near did so. But at the last second, I thought " No, I'll check on it one more time first." Man!! Am I glad I did so!! I discovered it had stalled, and was literally smoking it was so hot!

While looking for a new motor, I found many complaints of this happening, apparently even when not overloaded as I had done.

The new motor arrived today, (quite fast). If I get a chance, I'll see what fitting it is going to take later today.

Vettepilot

I have two of the single drum HF tumblers and have been using 110 pieces of .45 caliber FMJ bullets as media. They fill the drum somewhere between 1/4 and 1/3 full, and they seem to be enough to do the job when I tumble for 8 hours. These are 230 grain bullets so 110 of them would weigh 3.61 lbs by my calculations. I process 200 grams of powder at a time so that's another 0.44 lbs for a total of 4.05 lbs, which does exceed the limit listed on my tumbler which is 3 lbs. So far I haven't had any problems, but I have heard of the motors stalling and overheating.

Obviously we don't want something red hot near our milled powder but I have to wonder just how dangerous it really is. The motor is some distance from the rubber drum which I don't think would easily be ignited. Before that ever happened I would think the motor would get hot enough to melt some of the very fine wires in the windings which would result in an open circuit. At that point the current would for all intents be turned off and no further heating would occur. I could be wrong but that seems logical to me.

If the drum somehow got stuck and the motor continued to turn I think it would quickly burn through the belt after which the motor would just be free wheeling with no load so it wouldn't overheat. Again I could be full of baloney but that seems right to me.

Still there would be advantages to a stronger motor. Sometimes I need to push start my drums to get them turning but once started they continue to rotate for the next 8 hours. So far at least.

VettePilot;
On your small mill motor? When I got mine apart, and was really looking things over, I think that a guy could pretty easily direct drive the driving shaft. It already has a milled flat on it, for the pulley set screw. Eliminate the pulley and belt and choose the size of the main shaft you want, to drive the barrel at the proper speed.
Another thing I thought of, while in this little project.

Maybe I'm missing something here but it seems to me that if I hooked the motor up directly to the driving shaft I could never get that shaft small enough to get the speed low as needed. I just looked it over and didn't take any measurements but the motor turns at 3400 rpm according to the plate and I'd guess the ratio of motor pulley to drive shaft pulley is somewhere around 10:1, and the ratio of the drive shaft itself to the drum is in that same ballpark, meaning there would be a total reduction of 100:1, so the 3400 rpm at the motor output would give 34 rpm to the drum. And that's (roughly) the neighborhood that it turns.

Therefore to achieve the entire 100:1 reduction solely by the drive shaft it would need to be so thin that it had no rigidity nor traction to drive the drum. At least that's how it seems to me.

I can however see how direct drive would be nice. No more belts to break. I'm thinking along the lines of using speed control of the motor to replace the reduction presently supplied by the belt/pulley setup. I don't think there's any practical (cost effective) way to control the speed of a small single phase AC motor like this but I'll bet it could be done with a DC motor and a variable output power supply. I'm thinking along these lines because I previously built an annealing machine for use in my reloading of modern rifle cartridges and it uses such a setup for it's two drive motors. The motors and power supplies weren't all that expensive either. I'd need some bigger pieces for this project but you've got me thinking. I'll have to research costs.

I have to say we've got some creative thinkers here and I appreciate the ideas they're putting into my head.

[Vettepilot]

All you said about the drive ratios is true. I think you've forgotten one factor though. When the final output/drive is reduced, the torque is increased. That's how such a tiny little 25 watt motor can turn a heavy drum at all. If one took out one of the two drive reductions in the system by running the motor to drive roller direct, it would increase the load on the motor by a large amount. It can, and has, been done in some mills, but the motor must be stronger to allow it.

This is also related to why it's worrisome to increase the speed of the rather weak HF mini mill by enlarging the drive roller. This change in the ratio increases the load on the already weak motor. Now that I have a motor that is 3 times stronger, I would like to do that though. DoubleBuck; I've never heard of 7/16" fuel hose. Can you elaborate? (1/4", 5/16", and 3/8"---> then 1/2" are the normal sizes you find.)

EDIT TO ADD: If you do look into designing a mill with variable speed, note that as you stated, DC motors can be rpm modulated. But AC motors with brushes can too. Single phase AC induction motors, (those AC motors without brushes), cannot easily be rpm controlled. Our friend Harbor Freight even sells AC motor speed controls for brushed motors.

Having rpm adjustment on a mill is versatile and interesting, and a worthwhile thing IMHO.

@ LINDSTROM:

Your knowledge of wood, charcoal, and chemistry is impressive, and I always find your posts a great pleasure to read!

Vettepilot

[Vettepilot]

When thinking of, and/or modifying or working with mills, I think basic milling is good to keep in mind. It's not quite as simple as it seems at first glance, with regard to mill speed, and milling media. If you go back and look up the reference link I posted on milling, it is very, very interesting; particularly the drawings and videos on the effects of mill speed.

Think of what many have been first exposed to the idea of milling by; the hobby of "rock tumbling." With rock tumbling, what you want is a rolling over and over, grinding action. This polishes the rocks into the glass smooth finish we are all familiar with. In this case, you want to certainly avoid the mill's "critical speed", as when a mill approaches "Critical Speed", there tends to be a more cascading, falling action of the media, and less efficient grinding action. For rock polishing, and similar duties, you want the grinding/polishing action, not the impacting, cascading media action.

Black powder was made commercially by milling using huge "Incorporating Mills" with giant, several ton wheels. This is because the black powder components need to be smashed up (pulverized) into the finest elements possible, and ground together. (Incorporated) They really spared no expense nor effort in making their powder, and if ball milling were better, they certainly would have done it. But they did not.

Grinding, milling wheels weighing several tons, and the machinery to operate them are somewhat out of the realm of easy construction and cost for our home brew BP efforts. But some enterprising soul found that ball milling could be made to work. Now remember the goal and necessities however. The components need to be thoroughly pulverized and incorporated. This somewhat takes a ball mill out of it's normal grinding/polishing role. For this reason, I think it is actually better to use the slightly faster mill jar speed. This gets the mill closer to "Critical Speed", and into the range where some of the media is cascading and falling. This causes a milling action whereby you have impacts, which pulverize, and rolling/grinding action which mixes and incorporates.

With my mill, which has rpm adjustability, I can clearly hear what the mill is doing, which is pretty neat. Quite obvious too. When at "standard" milling speeds, you can hear a rather steady, droning, grinding sound. As you slowly increase speed from there, it will suddenly hit a speed where the sound increases dramatically, and becomes less "steady" and more "crashing". (The sound is actually somewhat obnoxious and loud with my PVC jars.) I think this is where my most efficient milling for black powder occurs.

Just my uneducated thoughts and observations on the matter guys...

Vettepilot