Troubleshooting Black Powder Production

[AlB]

Hello folks, I hope you can help my solve this problem.

I have been attempting to produce black powder - I got my ball mill, my scale, my sulfur, my KNO3, my lead media, everything nessecary to do the job. I put together a 75/15/10 BP mix and milled it for an hour and a half. I then filled a PVC length of pipe about 90% full, capped on both ends, drilled a hole on one side, ran some fuse in, taped the fuse, and lit it.

Now, unfortionately, it did not have the desired effect. I was hoping for a simple retort, like in my tests with commercial black powder. What happened was that when the BP ignited, it produced an initial loud noise, but then the pipe was simply consumed in flame - meaing that the BP failed to detonate.

I am hoping someone can help me diagnose what exactly went wrong here. I came to a few ideas myself, maybe someone can confirm or rule out these:

1) Maybe I left too much empty space inside the pipe?
2) Maybe I left too little empty space inside the pipe?
3) Maybe my charcoal was poor. I was careful to select a "Natural" charcoal(no additives, as I am aware such charcoal produces poor BP).
4) Maybe I simply did not mill the BP long enough (1 hour 30 minutes approx.)

Do any of these seem likely? Can anyone point me in the right direction as far as figuring this out? Comments? Suggestions?

Thank you very much in advance,
- AlB

[nbk2000]

pipe about 90% full, capped on both ends, drilled a hole on one side,

And it's at this point that the Angel that looks out for fools and little children earns his pay. :rolleyes:

You NEVER drill into a device that has a reactive filling of any kind!

Now, to your questions;

1. Moot point as the device did ignite.

2. Not possible without a hydraulic press.

3. Possible, as some charcoals are inferior, despite being 'natural'.

4. Quite likely the cause.

It's usually considered good to mill each ingredient seperately, then to mill together with a percent or two of water, then dry.

Also, the material really needs to be consolidated under high-pressure and granulated for it to burn efficiently, otherwise it's not really gunpowder, more like lift-powder.

[CCC]

I read many articles said that BP mixture are milled with water, I think this is safety purposes but I want to know how to dry them, Naturally or with any devices??? KNO3 will crystallined again when mix with water and dry??

[tomu]

Even with an efficient ball mill of the Sponenburgh type milling will last at least 3 hours or longer to make good quality BP. If your ball mill is a rock tumbler milling time increases to more than 10 hours to get anywhere near good quality fast burning BP.

Polverone is the way to go without the need for milling.T

Pressing and granulating is imperative for use in salutes, guns etc.

@CCC

I strongly advice against wet milling BP, it's a real mess. BP can be milled with non-sparking milling media without any problems.

To prevent KNO3 from cristallizing out large quantities of aceton or ethanol is added to the BP slurry. This is of course expensive and dangerous because of the flammable fumes.

To speed up drying of BP and other mixtures a deep pan of dry sand covered with tin foil could be preheated in an oven to about 80° C taken out of the oven when thoroughly heated through and the composition spread thinly on the tin foil. The sand in the pan acts as a safe heat source which will release the heat over some time without the danger of getting hotter than the initial temperature.

[ChippedHammer]

Its hard to use BP and make a good salute, it will tend to blow the ends off or force its way through the fuse hole. Its possible but you need to make the tube so that the weakest point is the walls.

Crap starting materials will net crap product

[hst45]

1) Mill it longer; try 6 or 8 hours minimum, up to 16 if your mill and media are particularly inefficient.

2) Take the milled meal, wet it with 70/30 water/ethanol, and press it through a screen. A simple window screen will do. Dry these grains for a day or two, and attempt the same project. Your results should improve dramatically

[AlB]

Thanks for the advice folks. Seems to me like I just didn't mill it long enough.

Oh I did not drill the cap with BP inside - I am all too aware of the dangers involving BP and friction. Thanks for pointing that out though.

Some small follow up questions:
1) What does the addition of water do exactly?
2) Can I add water without getting involved with ethanol and such?
3) Will pressing it through a screen granulate the BP?

Thanks!

[defiant]

As NBK noted, not all charcoals are equivalent. Check out the different charcoals at http://skylighter.com/mall/chemicals.asp?Sort=C (i.e. "air float" charcoal).

[nbk2000]

Tomu, the water is added in such a small amount that the BP isn't even really damp, let alone mushy.

The water just helps everything mix better and is well established procedure in commercial BP factories.

[Bacon46]

I agree with NBK.

Could be the charcoal but you probably didn’t mill it long enough.

I use Diablo brand natural Mesquite charcoal. It is readily available in groceries stores the southwestern US for around $1.00 per pound and it performs very well. I crush the large pieces by placing them in a bucket and hitting them with the end of a steel pipe. Once the charcoal is in manageable pieces I ball mill into Airfloat.

When making Black Powder I ball mill the composition dry for 10 to 12 hours, moisten it with shellac and push it through a wire mesh pencil holder I picked up at the local office supply store. It’s courser than window screen and I prefer a course grain Black Powder.

All I use Black Powder for is a propellant. When I want to make noise I use a 2:1 KClO4 / Al flash powder. Drilling a hole in a pipe loaded with BP is stupid enough, don’t even be doing that with a pipe loaded with flash composition or we will be reading about you in the papers.

[AlB]

nbk2000:
Thanks for the info. I will add water to my BP - But at what point should I add the water, and how much?

defiant:
Having trouble viewing that link. On a related note, what is air float and activated charcoal?

Bacon46:
Thanks for your concern. But I already clarified in my previous post that I was not drilling the pipe with BP inside.

Diablo brand natural mesquite charcoal, hmmm? I will check it out man, thanks for the advice.

[defiant]

Google it. You've got the key phrases.

[CCC]

Tomu, many thanks for your experience.:)

[ucorky]

I had a similar issue in trying to make useful lifting powder. My issue was not enough KN03 but man I milled the living hell out of the whole batch before these guys put me right on my mixture. I used a modified rock tumbler unit for milling.

[tomu]

@AIB
First reduce your large charcoal chunks fromthe bag to small chips, mill this chips to airfloat charcoal dust. Mill all other ingridients if necessary (coarse KNO3, sulphur chips etc.).

Weigh the necessary quantum of all ingridients e.g. 75/15/10. Mix weight ingridients dry in a suitable container, now you've got what is termed green meal. Now is the time to add between 1% - 2% water with a sprayer/mister and mix it in. After this step you mill the stuff.

My exprience with milling such a damp green meal is that it cakes up badly in my ball mill (20 cm Sponenburgh-type mill). Even milling KNO3 without prior drying just gives a hard cake (I always dry it prior to milling and add some charcoal powder 1%-3% to prevent cakeing).

My way of making green meal is wet mixing it like in Polverone/CIA production. The KNO3 is dissolved in boiling hot water this is added slowly to the premixed charcoal/sulphur and this stuff is than dried (I don't add any ethanol or aceton, I just dry on the sand drying bath) and after thoroughly dry, milled for about 3 - 4 hours.

If you want to granule your BP by screening it through a window screen/sieve, you should add up o 5% of dextrin to the BP. Do not add the dextrin to a wet BP only to dry BP. If you added to a wet or damp BP it will build up clumps and don't blend with the BP meal powder. Blend the dextrin well with the dry BP meal and than add enough water to make the whole stuff damp not dripping wet. Stirr well and let it soak for a few minutes. Than need the BP mix to a ball and rub it through the screen/sieve. Collect the granules and let them dry. Ready to go.

Btw. if you don't have dextrin wall papaer paste (methlycellulose) works quiet as well, you just add a little bit less of it to the green meal.

Everyone has his own way of making BP so there are several ways to go about it. Mine is certainly not the ultima ratio, but it works for me.

Have fun!

[nbk2000]

Take a small sample, weigh it if possible, and measure the amount of distilled water you can add to it before it becomes moist. Then use less than that for your larger batch. Use a spray bottle to mist the water evenly so you don't get any soaked spots that'd crystallize.

[Bert]

The use of a small quantity of water in the milling stage was a common technique in commercial BP manufacture, and references to this are wide and near universal in historical accounts of powder milling- However, the mills being used in these descriptions were EDGE RUNNER mills, not BALL mills. For a ball mill, I have found that it is unnecessary and generally a pain in the ass. A small amount of water or (better) water/alcohol mix need only be used to help consolidate the milled mix into "cakes" for granulation.

Making BP is a lot like cooking. You can read about it to learn the theories about how and why different processes works all day long, but you will still have to get into the kitchen to see what results are obtainable with your equipment and materials. Even the 75:15:10 ratio is not set in stone, depending on incorporation process and consolidation pressures, other ratios CAN give better performance.

[Pb_Producer]

It could be the sulfur your using, I’ve been using garden sulfur which is a crapy green coulor and I've been having the same problems, recently I decided to refine it and the black powder worked a lot better. You can refine it by double boiling it and scooping off the crap on the top (beware of the sulfur dioxide its toxic). Unless you sulfur is a lemon yellow id try refining it.

Hardwood charcoal is also better, like oak, maple, apple, cedar, don’t use store bought briquettes.

The better your ingredients are the better your powder will be, the little things make a big difference in black powder.

[AlB]

I want to thank everyone who replied to this thread.

I guess there are really a lot of factors involved with Black Powder production - now I just wish I had more free time and money, to experiment and such, hehe.

Oh and by the way I have a Chicago Electric 6LB Dual Drum Rock Grinder that I use. I could not find an affordable alternative. Something that also occured to me is that perhaps I did not mill my charcoal sufficiently long, something that I think someone else pointed out. My KNO3 and Sulfur are both powdery, but the KNO3 could maybe be milled a little finer. The problem is cleaning out those damn drums each time. And how do you clean lead antimony media?

Thanks again for the comments and advice!

[Frunk]

The problem is cleaning out those damn drums each time.


I agree. By all means, if you get a tumbler with those rubber barrels, replace them with 4'' pvc pipe. The rubber is ridiculously hard to clean, it is full of pores.

[AlB]

I agree. By all means, if you get a tumbler with those rubber barrels, replace them with 4'' pvc pipe. The rubber is ridiculously hard to clean, it is full of pores.
Wow! That is a brilliant idea! Plus, by doing this, instead of having two 3LB drums, I could have one big 6LB one. Would the PVC caps stay on OK? Any other disadvantages of using PVC?

[Bert]

I have made PVC drums for a hobby rock polisher. I did not use commercial PVC fittings and caps as they were expensive, and of too large diameter to fit my childhood rock polisher's cradle. I made half a dozen, so I could have one dedicated to each oxidizer or chemical and not need to clean between changing chemicals. The project took an evening and cost less than $10.00. I had all the materials as scraps from other projects of mine (or my father's) except the plastic bonding cement and a box of 6-32 machine screws, however.

I took 4" DWV PVC pipe, cut it to length in a miter box and smoothed the ends by rubbing on 100 grit sandpaper sheets bonded to a sheet of glass. This constituted the body of the milling drum. As the inside was too slick for the media and charge to properly roll with the drum, I glued in two hardwood lifter bars with plastic bonding glue on opposite sides of the barrel.

To make the end caps I then cut circles of a piece of 1/4" masonite/melamine laminate somewhat larger than the OD of the pipe (I had bonded countertop plastic laminate material to both sides of this masonite with rubber cement to form a 3 layer laminate). I then drilled 8 holes equally spaced through the cap material and into the ends of the pipe of a size for a #6-32 tap. I tapped the plastic pipe, and opened up the holes in the laminated cap to clear the retaining screw's threads. I attached the caps to both ends of the pipes, and used a router table with a pattern following bit whose guide ran against the PVC pipe to reduce the caps to exactly the OD of the pipe.

In use, I glued one end permanently to the jar and used 8 brass 6-32 X 3/4" round headed machine screws to attach the other. I found it necessary to wrap a couple of turns of electricians vinyl tape around the openable end to prevent dust sifting out.

PVC generated a static charge in use. This could have consequences for milling black powder... I had to re-attach some of the lifter bars after some use, I would prefer to have made these of plastic attached with through the drum screws if I made such things again. I would fill these screw holes with silicone or similar glue to prevent powder leakage.

[Frunk]

PVC generated a static charge in use. This could have consequences for milling black powder...

Yes, I forgot about this. PVC pipe acts like a leyden jar under certain circumstances.You can use any kind of plastic pipe, like ABS, but test it before loading it with 1 kg of BP.

[rollie]

It could be the sulfur your using,...

You can buy very cheap 99.9%pure fine sulphur powder from eBay, as well as the KNO3, if you can't that anywhere;)

As for charcoal I have found that BBQ charcoal of any kind is too poor for fast burning BP. Far too many impurities I think. Initially I used airfloat charcoal from an art suppliers(Supposed to be for "finger painting") but it was too expensive for large quantities, so I made my own, with at first varying results.

I'll try and find the link I used for making charcoal, it was very comprehensive.

BTW I love BP and its uses. I haven't really dabbled outside of BP and flash powder and ammonium nitrate: diesel mixes.

+++++++++=

Don't quote whole posts!

nbk2000

[Secong Nature]

Ok heres my thoughts, I don't have a ball mill (yes I know on a roguesci forum and doesn't even have equipment) due to very poor practical skills and lack of motivation.

I'm intending to use a 20L PVC paint tin, its tapered slightly though, make my own media from old roof lead, mix of bars and balls I think, anyway you probable don't want to know this so...

About the static problem, could you use an electrical wire touching the mill and running to a dish of water or even the ground in order to dispell static?

Also the idea on multiple drums never occured to me though I'll be milling just BP for a while, I had to use a mortar and pestle, filtering it all through a tea strainer so I could get a decent quality, so a ball mill seems like the smart thing to do

[tomu]

Some thoughts about your intention of building a ball mill:

The mill jar must be filled half of it's volume with grinding media for efficient milling.

In your example of a 20 l PVC can that's 10 l of lead media, that's a lot of weight to lug around and my guess would be that the PVC can might not support this heavy weight.

Also the diameter of the milling jar is important for defining the right turning speed.

You will also need some heavy duty e-motor to turn this kind of weight.

Also the grinding media should always be of the same size otherwise the media will grind itself, which leads to less efficiency and contamination of the material to be grinded.

Grounding the mill and the jar will take care of the static electricity issue.

[Cobalt.45]

PVC will definitely stand up to the weight of lead media. What might not, are the rollers. Much less than 5/8" OD steel will flex.

I would suggest using 4" and larger ID for any type of milling, smaller becomes too inefficient.

The easiest and cheapest way (IMHO) to make a good, durable 4" jar is to use "test plugs" found at Home Depot and elsewhere for end plugs.

They require no tools to use, are removable for charging/emptying and cleaning. They fit inside the PVC ID, there's no issue with end plug or reducer fitting diameters.

This also allows the full length of the jar to ride on the drive roller so there's less chance of slippage.

By moving the plugs closer or further apart, you have an adjustable jar that allows you to tailor the volume of the jar to the amount of material you're milling. This becomes useful when you realize that the material being milled should represent 25% of the jar's volume.

Also useful is placing one plug in the center of, say, a 1 foot long jar, you now have two, 6" jars and can mill two dissimilar materials at the same time.

Or,
The 4" test plugs are ~$4.00/each and a 4' length of 4" ID pipe is ~$5.00, IIRC.

Do yourself a favor and search out the info that was uploaded by "justme" on constructing a proper ball mill, including what you need to know in re media, RPM's, HP, gear ratios, jars, etc.

It can be found here:
http://www.roguesci.org/theforum/showthread.php?p=90086#poststop

This is considered to be THE book on hobby-type ball mills.

[Secong Nature]

Thanks heaps, also the PVC bucket is 12L, not 20, I'm intending to use a washing machine motor or any other whiteware

[Cobalt.45]

Speaking of white goods, SWIM successfully uses a dryer, complete, as his mill.:D

The gist of it is a plastic bucket w/lid that's mounted permanently to the center of the dryer drum with 3/8" bolts, nuts and large washers X 4.

Into this, a PVC jar (usually 4" or 6" ID) is placed. It's centered with foam rubber from an old sofa. Exact centering isn't necessary, close will do.

The bucket lid is replaced, door shut and the timer set. It then runs 'till the buzzer alerts someone to restart it (if needed)- it runs for ~1 hour at a time.

The only modification made to the dryer was to replace the motor pulley with one about 2" larger OD so the RPM's were correct (~80) and drilling two holes so the belt tensioner could be repositioned.

Oh, and no heat is involved (fluff cycle).:rolleyes:

[nbk2000]

I'd like to see the explosion that would make if it ever went off. :D

Is the drier anywhere near your house?

[Cobalt.45]

The dryer drum is vented through what used to provide hot air to the atmosphere. I didn't mention that the cover over the heating element is also removed. The element went bad, so when the dryer was relegated to mill duty the cover wasn't replaced.

The drum is also vented through the dryer exhaust as well as the port on top of the cabinet where the filter used to go.

In addition, the door is held shut by a spring metal clasp and is not prevented from opening upon a (sudden) over-pressure situation.

The door can be left open for that matter- it's closed to reduce noise.

Additionally, the top of the dryer cabinet is held in place with spring steel clips that resemble a cotter pin with "hips". The "hips" protrude through a hole in the cabinet sides that are flanged and drilled to receive them.

When servicing the dryer, one would pry with a tool between the top and the side, thus popping the clips free of their holes. In other words, it's not bolted down.

The same thing would occur if the pressure reached the limits of the three internal passages and the door- the top would be able to fly open but not fly loose, it's hinged in the back.

It's run adjacent to an out building, under a kind of lean-to/ extended roof eave.

Current is supplied by switching the circuit breaker located ~75 feet away.

Far from ideal- it's just a way to save a buck while getting the job done.