Smokeless gunpowder problems

Making rocket motors? You do know that you are veering in to the "dangerously stupid" zone, right? I'm guessing the solvent idea is the right track, but I have no idea what would be appropriate. One of the firearm cartridge reloading manuals might have a chapter on how smokeless powder is made. You might want to study up on that and make sure your solvent isn't changing the smokeless powder into another chemical altogether. That is, if you value all your fingers. Check with the BATFE too, make sure you are not manufacturing a felony. Just out of curiosity, what brand and type of smokeless powder are you using? That stuff is around $20 a pound nowadays, right?

I suggest drying the lumps for a longer period away from heat and flame. That's close to how I remember they make smokeless powder in the first place. Red dot is pretty fast burning by itself, but if you're making large lumps, you will lose that property. So as long as you are making just lumps, check out the price on surplus "pull down" powder. Frequently it's a fourth of the price of the name brand stuff. Specific, calibrated burning rates that do not vary between powder lots are not needed if you are just making lumps. I also assume they can sell it cheaper because there's no consumer liability insurance. It might work well in your application. You do realize I have zero experience and disclaim all responsibility. Furthermore, IANASPM (I am not a smokeless powder manufacturer) Good luck with your secret plans. Take care of those digits. (and if you are making rocket motors, others have done it differently with cheaper materials)

 well if you want a hot violent burn, use a 50-50 mixture of powdered rust and powdered aluminium. then use magnesium ribbon as a fuse. in case that mixture sounds familiar; yes, that is thermite.

like this ?

yes it is

It looks like pyrodex or BP. Be REAL careful with the smokeless stuff. One of my experiments went horribly awry, leaving me deaf for a couple of days and metal splinters in inconvenient places!

I was trying to make a .22 faster. I was using a .22 pellet from an airgun, a black powder blank, and smokeless powder. I permanently damaged the rifle, and learned my lesson.

A little extra "solids" in the mix, such as gelatin, sugar or sulphur, will tend to stick the grains and add a little filler between the grains and sort of coat the individual grains.... altering the burning speed through the mass.

(The original single base powders were too hot and eroded the rifle barrels quite quickly - so they coated the grains with vaseline to cool the fire a wee bit and slow the burning speed down)

Without testing the burn times of say 20mm by 100 mm rods, and using varying mixtures and compression, off the top of my head I'd say that with the binders - you could get a burning rate quite similar to a rod of SOLID single base powder.

Might be quite nice in toy rocket engines......

If you want to get all scientific about it... mix up say 20 gram batches of powder using 2%, 4%, 6%, 8% and 10% binder (by weight or volume) - (sugar is as good as anything) with a single small drop of detergent mixed in a whole cup of water - and then press the damp batches of powder into some thin aluminum, steel or brass tubes iwth 6mm or so hole in the middle - all cut to the same length...

Stick them somewhere to dry in a hot place... for a few days and then press them out and have a look at what you have with a low power microscope.. to see how the grains have bound.. and the filling in between the grains.

I would NOT go adding oxidising compounds to the mix...

But the optimum issue is I guess to get a fast burning mass, that progressively burns as a solid from one ende to the other - and not as a flame front propogating through the block of grains...

The "right mix" of binder and powder will be the mix that shows a solid mass of grains cemented by binder with NO gap or flame path through the mass.. (or slightly gapped if you want to push it to the wire on large mixes)

A little excess binder won't make much difference, but significant excess amounts of binder will both slow down the burning time and add "dead mass" to the combustion process. (this may not be a bad thing either)

More or less exactly the same as a very RICH running car engine....

If your pushing for the peak power, and max pressure and fastest burning speed as a solid mass, then measure your mixes very carefully and examine the pressed rods under a microscope for the filling of the intergrain gaps with the binder and test the burning speeds.

I'f I was rocketing, I'd be doing the exactly slightly excess binder to the mix, rather than under doing it, because the lower the binder, the lower the gap filling between the voids and once the binder drops to a low enough level the rate of combustion will begin to progressively rise closer to that of powder being burn in a gun e.g. a "bullet being fired", rather than a rocket being accelerated...

The smart people in NASA call this "self disassembly" of the rocket motor.

But if you find your limits, and know exactly what you want to do... too little binder might be what you want... or too much binder might be what you want...

You MUST define exactly what you want without turning your rocket engine into a bomb... or doing nothing but smoke and even failing to get off the ground.

It's been a long time since I researched the manufacture of powers, so I might be wrong in the exact mix, but I think the original single base powders had about 5 or 6% vaseline...

http://findarticles.com/p/articles/mi_m0BQY/is_8_47/ai_76558924

Powder In The Modern Age

Modern, smokeless propellants date from 1846 when both nitrocellulose and nitroglycerin first emerged from European laboratories.

Nitrocellulose, or "guncotton" as it was once known, was produced by impregnating cotton fibers or wood pulp with nitric and sulfuric acid. The ensuing product was very unstable and difficult to work with, resulting in several headline-making accidents.

In 1884, it was discovered that the fibrous guncotton could be gelatinized by treating it with a mixture of alcohol and ether. The resulting product could be rolled into sheets, cut into squares and strips, and stabilized by adding up to 2 percent diphenylamine. This substance was named "Poudre B" by the French. It was the first successful "single-base" powder.

With great secrecy, the French exploited this breakthrough by designing the first smokeless, small bore, military cartridge, the 8mm Lebel, and a new rifle, the Model 1886 Lebel, to fire it. The French "Poudre B truly revolutionized military small arms.

One of the intriguing qualities of nitrocellulose is that it is the basic material in many harmless, domestic products including celluloid plastic, early photographic film, rayon, fingernail polish and lacquer. Not that such items couldn't be converted to other uses. An old article in National Geographic describes tribesmen along the Indian border with Pakistan who were adept at producing gunpowder by dicing up nitrocellulose movie film.

In 1888, Alfred Nobel took smokeless powder production to a new plateau by using nitroglycerin to gelatinize nitrocellulose, thereby producing a new commercial smokeless powder named "Ballistite." The effect of the nitroglycerin was to increase the energy of the powder. Ballistite was the first commercially viable "double-base" powder and was produced in 1889 at the Nobel factory in Ardeer, Scotland.

In that same year, the British patented a combination of 58 percent nitroglycerin, 37 percent guncotton, and 5 percent vaseline. The resulting paste was squeezed through a die to form strings or cords, and the resulting product was named "Cordite."

So by 1890, the essential chemistry of modem smokeless powders was well established. We still work with single-based powders exemplified by the IMR series, and double-based powders common to the Alliant series and Winchester ball powders. Formed into cords, flakes, sticks, and balls, modified with stabilizers, surface treatment agents, flame reducing agents, de-fouling agents, and blended to produce a fairly consistent level of performance from lot to lot, canister-grade smokeless powder sold at your local gun shop is a chemical marvel and an exceptional value.

Holy humongous comment, batman!

ooo, big comment

*scratches chin* I kinda think that making it a solid grain would make it more like a rocket motor, or serpentine black powder, if a big fireball is desired perhaps a flammable liquid?

you can get 'slugs' of powder for BP weapons, is that what you are trying to do? part of your problem is your solution : ) gunpowder burns fast because of it's size and shape, not just it's chemical composition. look at the side of your powder can-it has a rating for size of grains. the larger the grains, the slower the burn and you are making one hell of a huge grain. you are expecting the powder to act as a high explosive (like a primer-detonates by pressure wave not flame) when it isn't. you need to take a look at what you are trying to do with a better understanding of how it's suposed to work. ps C4 burns in open air, it needs a pressure wave (detonator) to set it off as a high explosive.