Sciencemadness Discussion Board

Fact Check-Smokeless Gunpowder from Scratch

Philosophazer - 2-6-2021 at 11:34

I’m writing a post-apocalyptic novel, and I need some fact-checking on how to do some chemistry more or less from scratch. Here are the rules:


1. The story takes place about fifty years after any kind of industry tanked.
2. The story takes place in a remote, isolated rural community locked in tribalistic war with some neighbors, but also participating in rudimentary trade with others.
3. The economy is based around trades and subsistence agriculture. There is also a nearby mine with access to coal, pyrites, and limestone.
4. There is no easy access to catalysts like platinum and palladium (I know, someone could probably scavenge them from old catalytic converters, but I’m not allowing that, because reasons).
5. No electrical grid, and spotty local generation at best. Most people have learned to do without.

What could a smart man with a reasonable amount of printed literature accomplish towards creating explosives, smokeless gunpowder, and nitrogen fertilizer, given several years of concerted effort? Here is what I have so far:

I first thought about gelatinizing guncotton in nitroglycerin, but I deemed the production of the latter too difficult and too dangerous for an amateur, post-apocalyptic chemist to attempt on anything larger than a laboratory scale (if I’m wrong on this, please say so).

For guncotton, three ingredients are necessary:


1. Cellulose: this should be absurdly easy to obtain.
2. Nitric acid: This will be produced by combining KNO3 with H2SO4 and heating. The acid condensed from the gas product should be nitric acid concentrated enough to fume. Because of a not-great shelf life, this will need to be produced shortly before use and stored in airtight containers kept away from the light.
A. KNO3-Fixing atmospheric nitrogen seems to be prohibitively difficult and costly outside of an industrial setup, so I’m assuming a reasonable supply from an already existing black powder operation, which extracts the nitrates from decomposing organic matter (of which nearby farms should have an abundance).
B. Sulfuric acid-See below
3. H2SO4-Obtained using something like the chamber process. You could roast some iron pyrite in a kiln, run the chimney into a lead-lined chamber, and spray the SO2 with water fed through a nozzle, either scavenged or custom-made. Collect the liquid at the bottom and distill it to obtain reasonably concentrated sulfuric acid. Apparently highly concentrated sulfuric acid production requires SO3, but most of the methods I looked at required some sort of catalyst.

I wasn’t super clear on this, but is the nitration process exothermic? If so, you could control the temperature either by waiting for cold weather, using ice cut from ponds and stored in cellars, or hooking up a bicycle to the compressor on a freezer and getting a tremendous workout.

Wash to remove residual acid

Here is where I’m stuck: in order to make a reasonable propellant, it seems like the nitrocellulose needs to be gelatinized somehow. It dissolves in acetone, which I suppose you could make from vinegar, but doesn’t the acetone ruin the guncotton’s explosive properties? Early smokeless gunpowders gelatinized the guncotton in ether and alcohol. Would regular ethanol work? Obviously, nitroglycerin would be ideal, if I could be convinced it would be safe enough to produce (you could make the glycerin as long as you had fats and quicklime).

What could one use to stabilize the powder?

After that, it’s a simple matter of standardizing the grain size, extruding through a perforated metal plate, and determining the ideal charge size.

Feel free to critique my thinking, offer your own insights, or fill in critical details I might have missed.

[Edited on 2-6-2021 by Philosophazer]

[Edited on 2-6-2021 by Philosophazer]

[Edited on 2-6-2021 by Philosophazer]

Metacelsus - 2-6-2021 at 12:00

Nitroglycerin is actually easier to make than nitrocellulose. The glycerin can be obtained from fats.

With nitrocellulose, controlling the degree of nitration is important. And mixing is not as easy since cellulose is a solid.

[Edited on 2021-6-2 by Metacelsus]

ShotBored - 2-6-2021 at 12:08

There's a lot of resources to work with for a prepper with a flash drive. I'm not super knowledgeable on current industrial methods for nitric or sulfuric acid but I might be able to lend some info on the NC synthesis process.

The process of nitration is fast and exothermic typically. Not only is it recommended that the reaction vessel be place in an ice bath, but typically I chill the H2SO4 and HNO3 prior to use as well. Another process you want to remember is that the NC needs to be reduced/neutralized after synthesis. This is typically done with a wash of sodium bicarbonate or sodium carbonate, but potassium carbonate/bicarbonate should work as well. This removes excess acid.

As far as stabilizer is concerned, the concern is always that your stabilizer will decrease performance of the NC. The compounds I typically use would definitely not be available to a post-apocalyptic pyrochemist...i believe historically, single-base NC propellants were stabilized with calcium carbonate or magnesium carbonate before industry started moving to diphenylamine/akardite/ethylcentralite.

Alkoholvergiftung - 2-6-2021 at 12:32

Instead of Guncutton you could make Collodium wool. 3 parts sulfuric acid an one part potassiumnitrate. Pure the sulfuric acid over the nitrate (finly crushed) after few minutes dump the cutton inside and hold it 15-20 minutes in the acid. The product burns fast but with little carbon remains. Mixed with nitroglycerin you can make Ballistit. Collodium is an better soaker for Nitroglycerine. Every nitration over 40C yields only Collodium but it nitrates a lot faster than under 30C for guncutton.
I would wash the cutton, jute or moss(pure cellulose too)in hot 10% soda solution to remove fad acids. after nitration with 1% bacingsoda and after that in concentrated urea solution(stabilizer and eliminates NOx)

[Edited on 2-6-2021 by Alkoholvergiftung]

[Edited on 2-6-2021 by Alkoholvergiftung]

Johnny Cappone - 2-6-2021 at 12:52

The problem with these post-apocalyptic stories is that they simply would never be as they are told.

I mean, where did everything out there go? Regardless of what caused the fictional apocalypse (nuclear war, epidemic, zombies, etc.) I'm sure that somewhere there still remains a processing plant/factory with a silo where 100 metric tons of nitrate rest peacefully. There would certainly be billions of Watt hours worth of solar panels strewn across roofs and small, easy-to-maintain, durable gasoline generators out there.

Literally billions of sealed batteries filled with sulfuric acid, strewn across the streets under the hoods of the billions of cars that once belonged to those who perished. Countless guns in police departments, shooting clubs, private collections and army warehouses.
There would likely be more ammunition, weapons and supplies than the survivors could use for the next 200 years.

But it's alright. An apocalypse in which the survivors just enjoy what industrialized civilization left before it was destroyed might not be an apocalypse worthy of a book. Or maybe it is, it just needs the author to strive to make the story exciting through elements other than having to manufacture his own food, weapons and explosives.

I suggest you ask yourself if a detailed description of the technical difficulties faced by the character in preparing the nitroglycerin is really necessary. I mean, can't you just declare that he did it, providing only details that don't imply exposing the problems that are slowing your writing? I love it when the books and cinematographic works I'm consuming have a certain degree of scientific precision, it makes the story so much more immersive. But unless you're writing for a scientifically educated audience, I don't think you need to go into such small details. I mean, is the average reader really going to care to know the minute details of how our post-apocalyptic chemist-farmer-warrior stabilizes his explosives?

Alkoholvergiftung - 2-6-2021 at 13:30

The greater problem would be the weapons for the smokless powder. Black powder is much more saver i dont think in an apokalcptic cenario you can make barrels that can hold the high pressure of smokless powder.

Fyndium - 2-6-2021 at 13:33

Apocalypses are hypothetical. Most likely there will be an evil empire with evil factories supplying at least the other side with evil ordnance.

But alongside of that, nitrocellulose gunpowder is critical in ratios, but also on the extrusion size of grains. Hence there are huge selection of different gunpowders for all kinds of calibers, from slow-burning to very fast burning. Choosing wrong could blow up your gun, or cause majority of the propellant burning ex barrel. Variations in grain size cause variations in muzzle velocity, and as this is not that of a biggie in a rudimentary API blowback gun like 9mm, it would provide very detrimental in precision targeting of hunting nature, either for feedstock or for adversaries.

There was a source that stated that nitrocellulose based gunpowder could be cut with up to 64% in weight with PETN, and certain other secondary energetics without risk of detonation. This has interested me ever since, because sourcing secondaries could be easier than gunpowder, and could render commercial gunpowder source to supply 3 times more propellant that way.

Pyro_cat - 2-6-2021 at 22:36

Quote: Originally posted by Johnny Cappone  
The problem with these post-apocalyptic stories is that they simply would never be as they are told.

I mean, where did everything out there go?


Up in smoke.

When people stop cutting the grass it gets 4 feet high and the drys out hit by lightning and burns, and in most apocalypses there is no more fire department.

After a few years there would not be much left at all,

Always want to survive apocalypse but there won't be all this free stuff around for that long.






They always leave the inevitable firestorm out of apocalypse movies.



[Edited on 3-6-2021 by Pyro_cat]

tubbsfiredamage-e1519098966983.jpg - 55kB

Microtek - 3-6-2021 at 02:57

I agree that nitroglycerine would be just as easy as NC. NG is not nearly as sensitive as some fiction would have you believe, and is very unlikely to be set off by ordinary preparation and handling. Also, if you mix it with about 50% ethanol it becomes almost impossible to detonate, even on purpose. The ethanol can then be evaporated when preparing it for use. Acetone would be even better, as the NC could be dissolved in it to produce the double base powder, removing a process step.

For the chamber process, thermally decomposing a bit of nitrate to produce NOx will catalyse the SO2 -> SO3 reaction.

Alkoholvergiftung - 3-6-2021 at 04:14

so2 generator 3neck bottle and quarz pipe vanadiumcatalyst and you can make your oleum. Clay pot lead or carbon anode and you can make from epson salt 20% sulfuric acid.

Vomaturge - 3-6-2021 at 04:38

Quote: Originally posted by Pyro_cat  
Quote: Originally posted by Johnny Cappone  
The problem with these post-apocalyptic stories is that they simply would never be as they are told.

I mean, where did everything out there go?


Up in smoke.

When people stop cutting the grass it gets 4 feet high and the drys out hit by lightning and burns, and in most apocalypses there is no more fire department.
[Edited on 3-6-2021 by Pyro_cat]


now that's a scary apocalypse. Every square meter of dry land gets covered in grass and set on fire, including the ones where vegetation doesn't normally grow. Across every roadway, inside every concrete building, the grass inexorably pushes, preparing for the yearly deflagration front that starts somewhere random and steadily spreads across every continent, forcing all the animals and surviving humans to either tunnel underground or migrate fast enough to stay ahead of it until they can swim out into the sea, wait it out and slowly begin their trek back to reclaim their charred land...

When we look at history and archeological records from times when there were fewer people and less fire extinguishing technology, there were more catastrophic wildfires than today, and a few more cases of whole cities being gradually consumed by fire. But it's not like every section of the world was exposed to fire every fall. There are ruins like the buildings in the Chernobyl exclusion zone that could probably burn easily but they haven't all been destroyed like the buildings in the picture you linked. Conditions have to be just right for a fire to spread through a city, even without a fire department. Modern cities are also less flammable than Tokyo, Chicago, London in previous centuries.

Philosophazer - 3-6-2021 at 08:13

Some really useful responses so far. Being able to make and safely store NG simplifies things a lot. Microtek, thanks for the tip on catalyzing SO2-->SO3.

As far as the worldbuilding question goes (why not use the mountains of unused stuff left behind?), your mileage may vary, but I'm relying on a couple things to make the scenario feel more plausible:

1. There's at least 50 years of history between the disaster and the story proper. That's 50 years of deterioration and consumption, 50 years of essentially feudal warfare between squabbling communities, and 50 years of a die-off that slowed down without really ending. Do you folks think 50 years is too short a time to get to a point where people have to start making stuff on their own?

2. I'm banking on the erosion of human capital to be at least as inhibiting to progress as the destruction of infrastructure. In our modern, interconnected world, sulfuric acid is a valuable commodity. In a Mad Max world, who cares if you've got a tanker full of oleum? If you're not clever enough to get it all the way to a useful end product, market, and distribute it, expertise in any particular area won't do you much good. Rebuilding trade routes and supply networks is more difficult than stabilizing NC in this world.

3. The story takes place in an isolated area cut off from the vast majority of the rest of the world. Somebody somewhere probably did crack open a military armory and establish a little empire for themselves, but that wouldn't affect the setting of this story (at least, not until the sequel...).

Also, I'm not planning to go into too much detail as to the process, but I find it satisfying as a reader to believe that the crazy stuff I'm reading about isn't pure fantasy. And it's surprising what great storytelling opportunities fall into your lap with a little research. I'm not sure yet how I'll work in a character with nitrated clothing flashing everybody (pun intended), but you can bet I'll figure it out!

I don't want to get too off-topic (this is a chemistry forum, after all), but you guys had some relevant questions on how to source the raw materials. And hey, speculating about the end of the world is fun. It's partly why I wrote this thing to begin with.

Great ideas so far. Keep them coming!

[Edited on 3-6-2021 by Philosophazer]

Philosophazer - 3-6-2021 at 08:15

Quote: Originally posted by Alkoholvergiftung  
The greater problem would be the weapons for the smokless powder. Black powder is much more saver i dont think in an apokalcptic cenario you can make barrels that can hold the high pressure of smokless powder.


You're absolutely right. I'm definitely NOT going into much detail on how to forge a rifle barrel from scratch ;)

Fyndium - 3-6-2021 at 11:33

Actually, significant factor for manufacturing smokeless powder gunbarrels is not that of material strength, but durability. When a barrel must withstand tens of thousands of rounds, simple structural steel does not work. The higher strength is necessary for locking lugs, unless over-engineered, but the mere barrel and chamber can be successfully turned out from normal cold rolled steel, and some gun manufacturers use free machining steel to turn barrels (mostly for lower round count guns like precision, hunting and silhouette that warrant barrel change after few k shots, in some extreme sporting level even after few hundreds) due to cheaper machining. The barrels are first bored out from blanks with gun drill, then reamed, and finally a carbide button is pushed or pulled through with a hydraulic ram that makes the final, exact diameter and also forms the rifling at one pass. Modern, utility small arms are always churned out from top of the line materials like 4150 alloys to minimize weight to strength ratio, and because the material costs are anyway a marginal constituent of the whole manufacturing process.

If one were to make a gunbarrel out from scratch, there would be a possibility to use tamahagane style metallurgy, that produces more consistent quality steel with controllable carbon content. People have demonstrated churning out enduring knives from iron ore collected from natural source. The tooling would be of a bigger question, anyway. In a post-civilization era there should be significant derelict of useful metal and tooling.

I would personally go beyond lengths to bypass blackpowder for any small ordnance use. It is just very cumbersome and foul, low powered and if not prilled, will also cause component separation due to vibration upon it's own after time. It could possibly be used for some narrow applications, like big bore mortars, recoilless rifles etc that are single shot, low pressure by design and need large amounts of propellant.

Philosophazer - 3-6-2021 at 12:20

Quote: Originally posted by Fyndium  


I would personally go beyond lengths to bypass blackpowder for any small ordnance use. It is just very cumbersome and foul, low powered and if not prilled, will also cause component separation due to vibration upon it's own after time. It could possibly be used for some narrow applications, like big bore mortars, recoilless rifles etc that are single shot, low pressure by design and need large amounts of propellant.


That was my reasoning for making smokeless powder in the first place. Black powder could work in a pinch, but automatic weapons would jam in the short term and break in the long term. After a while, you'd end up with some fearsome arsenals of weapons with ammunition to use them. They might make nice decorations for a mantlepiece, but you'd rarely use them. Smokeless powder wouldn't just give you a tactical advantage based on burn efficiency, it would allow you to start reloading rifle cartridges for automatic weapons. That was my thinking, anyway.

[Edited on 3-6-2021 by Philosophazer]

Alkoholvergiftung - 3-6-2021 at 19:23

Fyndium. Interesting thing. Austrian-Hungiarn Army used Steel Bronze Barrels for the L18 Artillery during world war 1. They whre scraped 1918.
They are made buy casting 90% Copper and 10& tin into cast iron cocilles and then they pushed 5 different buttons throught the barrels every time a few millimeter wider so the walls got streched. Maximal caliber was 125mm.
If you have the knowlegs you can make out of crap usefull things.

Fyndium - 4-6-2021 at 12:04

Many old school techologies and methods of chemistry and machining and metallurgy are most interesting, because they are not dependent of megascale high-tech metalworks that can make proprietary alloys for specific use, or of machinery that costs millions and although is very efficient, also requires exact variables to work. Before CNC, parts were made with purpose-set workstation turrets, and for example German Mauser Kar98K had about 550 manufacturing steps. There was this one guy, whose only job was to drill extractor pin holes all day long with extractor-pin-hole-drilling-station. And they made millions of these.

During the age of sail, bronze cannons were notoriously valuable and unreliable. There were no proofing like nowadays, and it was commonplace for cannons to blow up, taking the crew along, every now and then.

But, like mentioned, gunsmithing can be as fine tech as it could be rudimentary, and purpose sensitive. For example, if someone wants to design an improvised semiauto SMG, the parts and barrel should have life expectancy of few k rounds at most, because that is the very likely lifespan of such device. Tesla company goes with this mentality - they scrapped all superalloys and fancy metals, and used plain stainless steel for their space program, and it works, is cheap and reliable, although maybe a little less efficient. It is also noteworthy that common carburizing using 70:30 carbon:CaCO3 at 800-900C will produce high carbon depth of up to 2mm in 2-4 hours, allowing for making many parts, like sears, blowback bolts, etc from ordinary 1010 steel and quenching and tempering them to very high strength. They used this method prior modern methods and alloys with high success, but the major issue was variation in feedstock metal quality - nowadays you can benefit the otc standardized structural steel, which has actually quite narrow margins for quality. Note that rebar steel on the other hand can have quite large variables.
Quote: Originally posted by Philosophazer  
That was my reasoning for making smokeless powder in the first place. Black powder could work in a pinch, but automatic weapons would jam in the short term and break in the long term. After a while, you'd end up with some fearsome arsenals of weapons with ammunition to use them. They might make nice decorations for a mantlepiece, but you'd rarely use them. Smokeless powder wouldn't just give you a tactical advantage based on burn efficiency, it would allow you to start reloading rifle cartridges for automatic weapons. That was my thinking, anyway.

[Edited on 3-6-2021 by Philosophazer]


Exactly. And, if the concept here is some sort of doomsday thing, you will not be making anything alone, but as a society. Hence, there should be a dedicated person with know-how that does their thing for 8 hours a day. If it is making smokeless gunpowder for specific caliber, then it is that.

Pyro_cat - 4-6-2021 at 16:57

Quote: Originally posted by Vomaturge  
Quote: Originally posted by Pyro_cat  
Quote: Originally posted by Johnny Cappone  
The problem with these post-apocalyptic stories is that they simply would never be as they are told.

I mean, where did everything out there go?


Up in smoke.

When people stop cutting the grass it gets 4 feet high and the drys out hit by lightning and burns, and in most apocalypses there is no more fire department.
[Edited on 3-6-2021 by Pyro_cat]


now that's a scary apocalypse. Every square meter of dry land gets covered in grass and set on fire, including the ones where vegetation doesn't normally grow. Across every roadway, inside every concrete building, the grass inexorably pushes, preparing for the yearly deflagration front that starts somewhere random and steadily spreads across every continent, forcing all the animals and surviving humans to either tunnel underground or migrate fast enough to stay ahead of it until they can swim out into the sea, wait it out and slowly begin their trek back to reclaim their charred land...

When we look at history and archeological records from times when there were fewer people and less fire extinguishing technology, there were more catastrophic wildfires than today, and a few more cases of whole cities being gradually consumed by fire. But it's not like every section of the world was exposed to fire every fall. There are ruins like the buildings in the Chernobyl exclusion zone that could probably burn easily but they haven't all been destroyed like the buildings in the picture you linked. Conditions have to be just right for a fire to spread through a city, even without a fire department. Modern cities are also less flammable than Tokyo, Chicago, London in previous centuries.



The 2020 Chernobyl Exclusion Zone wildfires were a series of wildfires that began burning inside Ukraine's Chernobyl Exclusion Zone in April 2020. The fires were largely extinguished within two weeks.

The Chernobyl Exclusion Zone is on fire and radiation levels are spiking

www.livescience.com/chernobyl-fire-spikes-radiation.html

Vomaturge - 4-6-2021 at 22:53

Okay, I was wrong about Chernobyl, it sounds like they still do supress fires there. I can't imagine people living say, 500 years ago were any more numerous, or any better at putting out fires than our hypothetical post apocalyptic survivors. Are there any trees or other heat sensitive items in existence from that time? Yes, trees can sometimes survive a brief exposure to a grass fire. So can a closed factory or silo or boxcar in many cases.

The idea that all the leftovers of society would cease to exist within a small fraction of a human lifetime? I'd say that would require a level of extreme wildfires that hasn't been seen in the entire geological history of the earth. No, the K-T event doesn't cut the mustard. Not even close. The sun becoming a red giant probably wont do the trick either, although it might achieve the same end result.

In my previous post I said what would be required for that to happen: a continuous flammable layer of plants would have to grow on every exposed surface, regardless of whether it was a suitable environment for them to grow. It would have to be completely unaffected by weather, primitive fire supression, etc, and thick enough that its burning would last and by thermal conduction heat the inside of sealed structures designed to be hard to ignite. There's a fair chance that this would screw up the ecology of every biome to the point that the land would stay bare until sea creatures could evolve sufficiently to take it back. That's assuming that it didn't cause some catastrophic change to the ocean's composition that wiped them out too.


This doesn't have much to do with the OP's question but I just don't think it's an accurate portrayal that wildfires will destroy everything humans have left behind in such short order if we weren't there to stop them.