Sciencemadness Discussion Board - Gun Propellants: Single, Double and Tripple based

Gun Propellants: Single, Double and Tripple based

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Bert - 30-1-2015 at 10:22

Thank you for posting pictures, but they are not clear and well lit enough.

Re-take just the one showing BASE of cartridge, well lit and detailed enough to see any small scratches , marks, differences in curvature of primer's edges.

Hennig Brand - 30-1-2015 at 10:35

These should be a little better I think. The one on the right held the homemade propellant. There is a little bit of fresh brass exposed in one spot on the casing which held the homemade propellant.

[Edited on 30-1-2015 by Hennig Brand]

franklyn - 30-1-2015 at 10:55

@ Hennig Brand

" This morning I dug out a 30-06 Winchester rifle "
Now there's a good prepper

" larger average particle size could have been the cause of lower performance "
Likely yes , you have not disclosed the milling methodology and subsequent sifting to achieve uniform grain size. This is the most important step since very slight change in particle size will greatly affect the burn rate. Uniform granular consistency is your goal to achieve consistent equivalent performance.
=> If you take any spectrum of granular material such as gravel inside a container and agitate it , the larger particles rise to the top and the smaller settle to the bottom. This action with nonuniform propellant will cause wider erratic performance.

" there did also appear to be more dark colored fouling in the cartridge which held the homemade propellant "
larger than average particle size will result in leftovers.

You have produced a quality substitute for the commercial product as your testing concludes. What more can one want. Kudos !

@ Bert

" The test you described made my hair stand up "
Well , if you fire die cast zinc Saturday night specials it might.

" Did case head flow brass into the gun's extractor cut out "
Jeez Bert, 20 % less weight of lower bulk density propellant isn't anything close to a proof load.
as Hennig Brand states :
" Since the homemade propellant was 60-40 double base, flake propellant, it was decided that a lighter load should be tried first."

" Your uncoated grains are likely degressive burning "
What matters is that the burn rate is way up consistent with pistol type powder. The area under the time / pressure profile determines the energy. Neglecting for the moment details like bullet seating depth and head spacing.

"Another factor in unburnt powder: A too large / non uniform grain size."
In that we can agree

.

Hennig Brand - 30-1-2015 at 11:58

I have been meaning to screen the flakes to separate them into different sizes. With the .22LR tests I did use a stainless steel kitchen sieve to collect fines which were used for those tests. For the 30-06 test everything was used (no separation). The propellant was poured out on wax paper in a thin layer (viscosity and layer thickness controlled by the amount of solvent/acetone used). Before the acetone had all evaporated (propellant about the consistency of fruit leather) a multi blade rolling cutter was used to cut it into flakes. The degree of particle size reduction was determined by eye and experience. Sieving the particles with a sieve stack would be a great way to separate the various particle sizes and greatly increase uniformity. Using a set of adjustable rollers, as suggested by Bert, would be more ideal as well to regulate flake thickness.

Thanks for the compliments Franklyn and also to Dornier 335A who I forgot to thank earlier. The propellant is a bit crude but it does work amazingly well. I was amazed at how close the muzzle velocities were, in the 30-06 test, considering the large difference in powder weights used.

Bert - 30-1-2015 at 13:05

Franklyn- look for my PM.

Making a functional double base propellant AT ALL is more than most amateurs will ever achieve. Working to accurately characterize it (and reliably replicate performance, batch to batch) is an order of magnitude beyond this.

I agree that the home made 60:40 powder is likely closer in performance to a fast burning pistol/shotgun powder than IMR 4895. Which is why up thread I suggested a small volume case and a cast bullet, fired in a strong single shot rifle.

The total area under the pressure curve isn't what worries me.

The HEIGHT of that peak, worries me, especially right at the beginning, before inertia of projectile is overcome-

I have fast, 30% NG content powders on my shelf that will CERTAINLY flow brass at case head, can perforate a case/rupture a primer and may damage or break a 30-06 rifle action (depending on type) with a 2 gram (31 grains!!!) charge under a 150 gr jacketed bullet. Total energy may be less than the 48 to 53 gr of 4895 I would probably use in such a rifle. BUT THAT DOESN'T MATTER.

Ironically, I also have slow burning powders that can damage a Garand with a heavy bullet by keeping the pressure curve up too long, and over pressurizing the gas system.

We should know the make of rifle being used for this test. It matters.

I handle explosives for a living. I teach and direct new employees to do the same. And I've been reloading ammunition since 1978. A conservative approach, with minimum exposure of your body to results of testing is strongly indicated. Luck doesn't last, only good technique gets you through.

A chronograph is a good start. A piezo strain gauge is indicated as well, unless a barrel can be drilled for a crusher mechanism or other such older technology pressure measuring equipment

Hennig Brand - 30-1-2015 at 13:22

I think that good consistency from batch to batch, in terms of NC & NG strength and purity, could easily be achieved. The next step would be to carefully control particle size and shape, which admittedly I haven't done yet, but it could definitely be done much better than I have done up until now without much trouble. Storage stability is a big one with smokeless propellants also, but I think we may have that under control as well with the easily purified MCNC and probably a stabilizer such as diphenylamine.

The propellant used in the test above is definitely not ideal for a 30-06 rifle, but it is serviceable. The rifle used is a bolt action 30-06.

[Edited on 30-1-2015 by Hennig Brand]

Bert - 30-1-2015 at 13:36

If I were going to make a rifle propellant, I would likely use something like this:

I own one. It is made of plated brass. The roller section is finely adjustable for thickness, and the cutter heads come in several widths- from angel hair pasta (square cordite?) to fettuccini (cross cut the strands into squares for "Poudre B"?)

Hennig Brand - 30-1-2015 at 15:15

I have been making propellant in 10g, or less, sized batches for testing. For practical sized batches I think you are on the right track. I should get one.

Bert, I do understand what you and Franklyn were talking about with faster burn rate/quicker rise in pressure and understand that flake propellants are not ideal for a 30-06 rifle. I also understand that a 30-06 is still at the end of the spectrum where it very much falls into the category of small arms. A 30-06 is much closer to a .22LR than it is to a lot of the guns that smokeless propellants are used in. From the bit I have read it also seems that the faster initial burn/quicker pressure rise can be compensated for quite a bit by using a smaller powder load often at the expense of some muzzle velocity. These faster burning powders, especially if double based and if overloaded, can be harder on barrels though, often stripping rifling from the breech end of the barrel at an accelerated rate.

Here is a very successful and famous cartridge that used flake propellant, though it was single base:

German 7.9x57mm cartridge, also known as the 8mm Mauser

The webpage can be found here:
http://www.cruffler.com/Features/JUL-01/trivia-July01.html

I made a pdf of the page also, which is attached, but the formatting is not perfect by any means.

Attachment: History and Development of the 7.9X57mm Cartridge.pdf (307kB)
This file has been downloaded 1058 times

Calculating Propellant Load Requirements using the Kinetic Energy Equation

Here is a simple method for determining the approximate amount of a given powder to use, using known values from an earlier test (bullet & propellant mass and muzzle velocity). This assumes equal burn efficiencies and equal frictional losses, etc. This simple comparison does not give peak pressures, but it is a very simple and effective way to get into the ballpark of what is an acceptable powder load.

Using the kinetic energy equation:

K.E. = 1/2 * m * V^2

It can be seen that kinetic energy is proportional to mass and to the square of velocity.

Comparing the results from the earlier .22LR test and later 30-06 test:

.22LR Bullet mass: 40gr
.22LR Muzzle Velocity: 1166fps
.22LR Powder load: 0.10g (1.54gr)

30-06 Bullet mass: 150gr
30-06 Bullet velocity: 2631fps
30-06 Powder load: 2.0g (30.8gr)

Powder load for 30-06 based on what was used for .22LR assuming equal efficiencies = (150gr/40gr) * (2631fps/1166fps)^2 * 1.54gr of propellant
Powder load for 30-06 = 29.40gr

Very, very close to what was actually used!

Once again, this doesn't give us the maximum barrel pressure, but it can at least give us a very good approximation of the appropriate amount of energy/powder to use.

[Edited on 31-1-2015 by Hennig Brand]

Hennig Brand - 31-1-2015 at 19:46

Of course I meant the proportion of losses due to friction and other sources were assumed equal for the above calculation.

Just read an interesting section from, "Chemistry of High-Energy Materials" by Klapötke.

"While single-base propellant charges (NC) are used in weapons from pistols to artillery weapons, the higher performance double-base propellant charges (NC + NG) are used predominantly in pistols and mortars. The disadvantage of the double-base powder is the strong erosion of the gun barrel (see below), resulting from the significantly higher combustion temperatures as well as the appearance of a muzzle flash because of the explosion of some of the combustion gases upon contact with air. To prevent erosion and the muzzle flash, a triple-base powder (NC + NG + NQ) with an NQ content of up to 50% is used, particularly in large calibre tank and NAVY weapons. However, the performance of triple-base powders is lower than that of double-base powders (Tab. 2.4). In a triple-base powder, particularly in large tank and NAVY cannons, NQ is replaced by RDX in order to increase the performance. However, the barrels suffer increased erosion problems again due to the significantly higher combustion temperatures.

The erosion problems in guns are generally caused by the formation of iron carbide (Fe from the gun barrel, C from CO) at high temperatures. Modern research on propellant charges is therefore focused on the development of powders which burn at lowest possible temperatures, but show good performance (see Ch. 4.2.3). Moreover, the N2/CO ratio, which lies at approximately 0.5 for conventional propellant charges, should be increased as much as possible. The formation of N2 instead of CO should also strongly reduce the amount of erosion, since iron nitride has a higher melting point than iron carbide (Fe3C) and furthermore, it forms a solid protective layer on the inside of the gun barrel. New studies have shown that the introduction of propellant charges which are based on nitrogen-rich compounds such as e.g. triaminoguanidiniumazotetrazolate (TAGzT) result in a considerably better N2/CO ratio and the life-span of high calibre NAVY cannons can be increased by up-to a factor of 4 [11]."

Double base propellants have a lot going for them, but they are, apparently, often much harder on barrels. Some powder companies are now advertising that their double based propellants cause no more erosion than their single based propellants, because of special additives, but I am skeptical of such claims at this point.

Bert - 31-1-2015 at 23:57

image.jpg - 11kB

Nitroguanidine- One of the first adjuncts to lower flame temp without sacrificing too much in performance, and still a good choice.

The history of cordite reformulations is representative of the early attempts to balance good propellant performance against acceptable barrel life.

History of cordite production

The first formulation @ 58% NG burned so hot, .303 barrels lost accuracy in under 1,000 rounds- The second formulation @ 30% was about as high as any common rifle propellant made since.

Cordite fell from use mostly due to performance and cartridge manufacturing limitations imposed by the grain (strand!) shape.

You could not blend different lots to standardize performance- This is typically done by tumbling different batches of grained powders together through a tall "blending tower", can't do that with cordite.

In manufacturing cartridges, the cordite was inserted into the case and then the shoulder and neck of the cartridge was formed. It is desirable to have the neck of a cartridge case annealed fairly soft, so as to allow expansion and a good seal against the chamber walls without cracking- Obviously, it was not safe to anneal the cartridge necks with the cordite already loaded.

If there were attempts to modify burning profile by coating cordite, I have not heard of it. For pistol rounds and some gas generator uses, it could be chopped into short pieces. The shorter the cut, the faster the propellant.

Additionally, they never did get cordite to be as temperature insensitive as might be desired- Cordite rounds had to be loaded to a fairly low pressure, if they were used at tropical temperatures (or allowed to "cook" in a hot chamber), pressures rose markedly. Similarly, at arctic temperatures the burn rate went low- I have seen old cordite rounds leave many thin remnants of the strands littering the snow when fired in winter.

But it was easy to make, easy to meter in loading- and evaded Nobel's Balistite patent...

Hennig Brand - 1-2-2015 at 12:23

Interesting post, Bert, I think for rifle I will take the hints and move towards using cooler propellants with less NG (20-30% NG perhaps). I took another shot from the .22LR and the 30-06 using the same propellant. This time I used a small kitchen sieve to separate the fines from the coarse flakes. Some of the fine flake (0.102g) was used to load the .22LR cartridge and some of the coarse flake (2.004g) was used to load the 30-06. I am at the end of or in between snow storms, with high wind and blowing snow, so it was difficult to get good chronograph readings (at least outside) and impossible to get pictures of the readings. The chronograph would show the reading and then within a few seconds a gust of blowing snow would go through and the chronograph would give an error message before I could get my camera out to take a picture. The difference between actual measured results and theoretical results obtained using the kinetic energy equation were different by 12% this time, which is more than I was hoping for. I hoped that using more accurate scales would result in closer agreement between theoretical and experimental results. I expect that the greatest difference this time is due to the fact that the fines were removed from the 30-06 propellant. Flake size appears to have a major effect on muzzle velocity from the .22LR and 30-06 tests done up until now (some earlier .22LR testing was not reported here). Regarding 30-06 chamber pressure, to be completely truthful this time the bolt did come up easier after firing than it did the last time after firing with the fines included (indicating lower chamber pressure with fines removed). This time the bolt could be lifted with just my little finger. A bit of fresh brass was exposed again on the end of the cartridge casing and I have determined that it is occurring while loading the shell. The reason for the exposed brass is that the shells are going in harder, which is happening as the result of an expanded and/or bent casing neck caused by the crude method used to pull the bullets.

Measured Quantities:

.22LR
Bullet Weight: 2.548g
Propellant Weight: 0.102g (flake, all passed through ~30 mesh SS wire kitchen sieve)
Muzzle Velocity: 1193fps

30-06
Bullet Weight: 9.671g
Propellant Weight: 2.004g (flake, none passed through ~30 mesh SS wire kitchen sieve)
Muzzle Velocity: 2543fps

Theoretical Propellant Load based on .22LR Results (assuming equal efficiencies) = (9.671g/2.548g) * (2543fps/1193fps)^2 * 0.102g = 1.759g

% Difference = (2.004 - 1.759) / 2.004 * 100% = 12%
Versus 4.5% difference last time

The fines were removed from the propellant used in the 30-06 this time and more accurate scales were used this time as well which could both have effected the results.

Pulled Bullets & Empty Casings.jpg - 211kB

[Edited on 2-2-2015 by Hennig Brand]

Bert - 1-2-2015 at 16:54

Optical comparator- Harbor freight, ebay or wherever cheap... Good way to characterize grain size, if you don't own a set of assay screens.

http://www.amazon.com/gp/aw/d/B0000WTZM2/ref=mp_s_a_1_10?qid...

Hennig Brand - 2-2-2015 at 08:58

Here is a microscope shot, at 40X magnification, of a fairly representative sample of the homemade flake propellant that was retained on the 30 mesh SS kitchen sieve and used for the last 30-06 test. The second shot, at 40X magnification, is the mm scale on a plastic ruler. Because of the thickness of the plastic ruler used, both the propellant and ruler could not be in focus at the same time.

Flake Propellant Microscope Picture.jpg - 278kB

And here is a 40X microscope picture of the flake which passed the 30 mesh sieve and was used for the last .22LR test.

Flake Propellant Which Passed 30 mesh Sieve.jpg - 298kB

[Edited on 2-2-2015 by Hennig Brand]

Hennig Brand - 2-2-2015 at 19:56

Here is a chapter from a text with a lot of good general information about nitrocellulose. Many interesting facts, for instance, according to this text single base propellants are made with ca. 80% gun cotton (13.4%N) and ca. 20%, 12.5%N NC.

The pdf was taken from the following university's website:
Universita' degli Studi di Napoli Federico II

Attachment: Cellulose Nitrate.pdf (272kB)
This file has been downloaded 1686 times

[Edited on 3-2-2015 by Hennig Brand]

Sub thread on high N adjuncts, removed from "quick questions, short answers" & merged with "bullet propellants"

Bert - 2-2-2015 at 20:20

Has anyone considered (or tried!) azodicarconamide as an additive to a high NG content double base propellant? High Nitrogen content, should be completely gaseous output, might speed burn rate as it does in some composite rocket fuels- While perhaps providing a cooler flame and maintaining high gas output similar to nitroguanidine?

World wide, used as a blowing agent for thermoplastics. In USA, it's a legal food additive! The only shipping restriction is as a flammable solid above a certain quantity. Seems to be rather easier to come by than "picrite" (nitroguanidine).

http://en.m.wikipedia.org/wiki/Azodicarbonamide

http://en.m.wikipedia.org/wiki/Nitroguanidine

[Edited on 5-2-2015 by Bert]

Bert - 2-2-2015 at 20:38

Ah, might just have re-invented the wheel. AGAIN..

Tons of referances, but for airbags, seat belt tensioners with ammonium nitrate, rocket fuels with double based propellants- Can't find anything yet on small arms propellants, cannon powders etc.

DubaiAmateurRocketry - 3-2-2015 at 00:55

what about NH2-NH-CO-N=N-CO-NH-NH2 ?

Pasrules - 3-2-2015 at 05:09

@Bert

I was doing some work in a PVC manufacturing plant in Australia when someone placed a cardboard box of azodicarbonamide underneath the mezzanine I welding on.

All I can say was it was lucky we had special class fire extinguishers.

Bert - 3-2-2015 at 08:58

Quote: Originally posted by DubaiAmateurRocketry

what about NH2-NH-CO-N=N-CO-NH-NH2 ?

I have not had enough coffee yet today- Common name or IUPAC of that?

Bert - 3-2-2015 at 09:22

Quote: Originally posted by Pasrules

@Bert

I was doing some work in a PVC manufacturing plant in Australia when someone placed a cardboard box of azodicarbonamide underneath the mezzanine I welding on.

All I can say was it was lucky we had special class fire extinguishers.

Welding and HazMat- What EVER could go wrong...

A while back, someone here in the USA at a freight forwarding facility told a welder to go put up some metal signs in the freight dock that handled hazardous materials. Right over where a shipment of FIREWORKS STARS, packed in cardboard boxes were stacked up, waiting for loading.

Dead welder, wrecked facility. And the hazmat rules in USA were changed. But rules don't help people who can't or won't read placards & THINK!

The PEPCON explosion started when a maintenance welder ignited building materials contaminated with ammonium perchlorate residue. Welder + management not thinking clearly = a couple of kiloton range explosions.

http://youtu.be/_KuGizBjDXo

http://nsc.nasa.gov/SFCS/SystemFailureCaseStudyFile/Download...

[Edited on 3-2-2015 by Bert]

Dornier 335A - 3-2-2015 at 09:33

Does azodicarbonamide burn that vigorously? The fire diamond on Wikipedia doesn't give it more than a "1" on flammability.

Bert, I can't find the structure anywhere but the name would be azodicarbohydrazide if I'm not mistaken. Googling that name gives no results what so ever though.

Bert - 3-2-2015 at 09:44

Azodicarbamide produces flammable gasses on decomposition, Carbon monoxide and ammonia. The transport regulations have some extra packaging requirements related to the ability of bulk shipments to explode strong containment in a fire.

DubaiAmateurRocketry - 4-2-2015 at 09:32

is it possible to use the azo group connect other energetic guanides and similar groups?

deltaH - 4-2-2015 at 09:39

Aminoguanidine is also being researched for this:

From the wiki article:

Quote:

Aminoguanidines and their derivatives are also being developed for energetic material applications. Thorough combustion of aminoguanidines can produce voluminous non-toxic gases, at moderate temperatures, with a minimum of smoke or dust.[13] This characteristic favors application to explosive gas generators for automotive airbags, and solid-rocket propellants that generate high thrust per kilogram, while emitting minimal visible smoke or infrared radiation (useful militarily as well as to reduce environmental impact). Aminoguanidines can also be used as precursors for the synthesis of tetrazole-based energetic materials and drugs.

, though the oxidised form:

weird.jpg - 8kB

is another interesting potential... don't know if it's possible though.

[Edited on 4-2-2015 by deltaH]

Bert - 4-2-2015 at 10:38

Yay! More candidates-

Propellant engineering and optimization with double base + high N adjuncts (now including these various non traditional & non energetic ones) would be a rather large project, if one followed all the paths. Perhaps we should do some engineering on paper before we start mixing chemicals... What Tesla said about Edison?

Quote:

“If Edison had a needle to find in a haystack, he would proceed at once with the diligence of the bee to examine straw after straw until he found the object of his search. I was a sorry witness of such doings, knowing that a little theory and calculation would have saved him ninety per cent of his labor.”

Hennig replicated ca. 1900 state of the art in a very short time, kudos for that. The next couple of steps will be more challenging, can we figure out how to work smart instead of hard?

And should the posts in this series get merged with the gun propellant thread? I do not think there's a quick answer to the short question coming.

[Edited on 4-2-2015 by Bert]

Hennig Brand - 4-2-2015 at 15:54

I was just about to do what was traditional and lower the flame temperature by going with a lower NG content double base or even single base propellant. However, high NG double base propellants have many advantages, just one of which is higher performance. One of the big advantages is that only about 12.6%N nitrocellulose is needed to produce double base propellants, whereas about 13.4%N guncotton is needed to produce high performance single base propellants which is more difficult to synthesis. It really would be great to find an additive, or component for a triple base, that would allow high NG content propellants to be used and still have acceptable barrel life.

[Edited on 5-2-2015 by Hennig Brand]

Trotsky - 5-2-2015 at 05:01

I've read that NC is soluble in ethanol up to about 11.8% N content. Is NC with high N content also insoluble in acetone, or does it retain solubility in acetone regardless of N content?

Is there a (nondestructive, preferably) way for the amateur to determine rough N content of NC?

Inspired by Hennig's posts I have been experimenting with home made NC powder for use in 12g shotshells. I have no experience reloading bullets, but I've spent hundreds of hours reloading shotshells, primarily 12 and 20g. I have gotten to the point of testing my powder in "blank" shotshells, just to determine the 'feel' relative to my usual load for clays (which I also made up some blanks of). I thought that for the amateur enthusiast a shotgun would be somewhat more forgiving than a rifle since less pressure is generated. My first trials weren't satisfactory, unsurprisingly, and I'm looking for a way to determine N content of the NC used from batch to batch for obvious reasons. I'm currently working on four batches, of which half is being nitrated under one set of conditions, and the other two under another, not so much to determine which conditions give me the best result, but to see how much variation I get between seemingly identical conditions. They're all smallish 15g batches, though.

Hennig, maybe you already discussed this somewhere, but what is your source of cellulose for nitration? I've been using washed cotton balls and it seems like a lot of material is lost as fines when neutralizing the acid and washing it. I thought washing it before hand, so I wouldn't be wasting nitration bath on fines I was going to lose anyway, would help eliminate that, but it still seems to be happening, though not quite as badly. I don't really want to try draining the liquids through a filter, since it's slow and I wash and neutralize many times before calling it good.

Trotsky

Hennig Brand - 5-2-2015 at 07:03

Celluloid cotton (ca. 10.5 - 11 %N) and gun cotton (ca. 13.0 - 13.6 %N) and everything in between is soluble in acetone. I just recently posted a good pdf as an attachment to a post earlier in this thread which will answer a lot of your questions.

http://www.sciencemadness.org/talk/viewthread.php?tid=22649&...

Apparently there are other methods for determining N content, other than a nitrometer, such as titration methods. I haven't tried them yet though. And I guess these are also destructive methods, which is not what you were looking for. If you don't lose very much material during nitration and washing the difference in weight, before nitration and after, can be used to calculate an approximate nitrogen content.

Shotguns do operate at much lower pressures than rifles you are right. The only thing about shotgun testing is that there is little warning between shots that the pressure is getting too high. It is definitely possible to split a shotgun barrel. With a rifle cartridge the bolt can get sticky, primers can flatten out, casings swell, etc, as pressures get higher than they should be which can serve as a warning as propellant load is increased.

At first I was using cotton balls, but lately I have been hydrolyzing cotton balls to make microcrystalline cellulose. When nitrating cotton balls I noticed a small amount of fines being lost during washing, but very little the last few times (ca. 0.1-0.2g for 10g batch). I think the amount of fines (fiber length) has a lot to do with the particular cotton source used and on the processes used as well.

[Edited on 5-2-2015 by Hennig Brand]

Stability Testing, Bergmann-Junk-Siebert-Test

Hennig Brand - 5-2-2015 at 07:15

I found this Los Alamos handout the other day which describes stability testing of explosives including NC. After reading about this from a few different sources, I do not think that this type of stability testing would really be all that difficult for the amateur. I think standard brewing airlocks could be used. Temperature control would be the only real technical issue, unless one had the proper equipment.

The reactions of interest if using the Siebert method and H2O2:

3NO2 + H2O <----> 2HNO3 + NO

2NO + HNO3 + H2O ----> 3HNO2

HNO2 + H2O2 ----> HNO3 + H2O

Attachment: Explosives Science - Information on NC Stability Testing.pdf (1.6MB)
This file has been downloaded 1132 times

Attachment: Bergman Junk Test Apparatus.pdf (85kB)
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Airlock 1.png - 46kB

[Edited on 5-2-2015 by Hennig Brand]

Bert - 5-2-2015 at 09:06

As a reference, National Center For Forensics: Smokeless powder database

Information on constituents and physical characteristics of various commercial propellants.

http://www.ilrc.ucf.edu/powders/search.php?resultPageSize=50...

No % given, only constituents. NC is assumed, NG and other ingredients are called out.

Hennig Brand - 5-2-2015 at 12:35

Here is another good article on smokeless propellant stability testing and stabilization and also a good picture and description of a commercial Bergmann-Junk testing apparatus.

Attachment: Testing the Chemical Stability of Smokeless Propellants.pdf (746kB)
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Attachment: Nitrocellulose Stability Testing Bergmann-Junk.pdf (103kB)
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Bert - 5-2-2015 at 14:27

Thanks franklyn! This is interesting looking-

http://www.dtic.mil/dtic/tr/fulltext/u2/595292.pdf

whoops ships in the night again

franklyn - 5-2-2015 at 14:35

Here it is again, updated post

http://www.sciencemadness.org/talk/viewthread.php?tid=1987&a...

http://www.sciencemadness.org/talk/viewthread.php?tid=8144&a...

Compounds of High Nitrogen Content in Propellant Compositions
www.dtic.mil/dtic/tr/fulltext/u2/595292.pdf

Dinitrobiuret & its Salts .pdf
http://www.sciencemadness.org/talk/files.php?pid=189115&...

Attachment: Dinitrobiuret - New Research Energetic Materials 2004.pdf (1.5MB)
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Attachment: Dinitrobiuret DNB thermal decomp.pdf (334kB)
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http://www.sciencemadness.org/talk/viewthread.php?tid=14033#...

Biuret from Urea .pdf
http://www.sciencemadness.org/talk/files.php?pid=189115&...

.

Pasrules - 5-2-2015 at 17:15

-Tetraazide-
Interesting how a double ligand can provide such amazing stability

http://en.m.wikipedia.org/wiki/Silicon_tetraazide

Hennig Brand - 5-2-2015 at 19:08

Attached is a report done by the Australian military. A mathematical model was created which takes into account chemical erosion, thermal erosion and mechanical erosion and allows comparisons to be made between different propellants. It is interesting that the propellants with the highest flame temperature are not necessarily the propellants which cause the most barrel erosion for a given muzzle velocity.

Attachment: Understanding and Predicting Gun Barrel Erosion.pdf (511kB)
This file has been downloaded 1275 times

DNT could be used as an additive to lower flame temperature, slow burn rate and reduce barrel erosion. DNT is something that has been used in North America for this purpose and it is fairly easy for the amateur to make. I have seen single and double base formulations that included DNT.

[Edited on 6-2-2015 by Hennig Brand]

Trotsky - 6-2-2015 at 06:21

Quote: Originally posted by Hennig Brand

Celluloid cotton (ca. 10.5 - 11 %N) and gun cotton (ca. 13.0 - 13.6 %N) and everything in between is soluble in acetone. I just recently posted a good pdf as an attachment to a post earlier in this thread which will answer a lot of your questions.

http://www.sciencemadness.org/talk/viewthread.php?tid=22649&...

Apparently there are other methods for determining N content, other than a nitrometer, such as titration methods. I haven't tried them yet though. And I guess these are also destructive methods, which is not what you were looking for. If you don't lose very much material during nitration and washing the difference in weight, before nitration and after, can be used to calculate an approximate nitrogen content.

Shotguns do operate at much lower pressures than rifles you are right. The only thing about shotgun testing is that there is little warning between shots that the pressure is getting too high. It is definitely possible to split a shotgun barrel. With a rifle cartridge the bolt can get sticky, primers can flatten out, casings swell, etc, as pressures get higher than they should be which can serve as a warning as propellant load is increased.

At first I was using cotton balls, but lately I have been hydrolyzing cotton balls to make microcrystalline cellulose. When nitrating cotton balls I noticed a small amount of fines being lost during washing, but very little the last few times (ca. 0.1-0.2g for 10g batch). I think the amount of fines (fiber length) has a lot to do with the particular cotton source used and on the processes used as well.

[Edited on 5-2-2015 by Hennig Brand]

I was going to measure the difference in weight, so I was very carefully rinsing the cotton balls neutralizing them. I had gotten them completely white (I am using drain cleaner sulfuric acid, and with the AN added, the bath turns a pinkish color, which the balls hold until they're well rinsed). The only time I've ever had a 'runaway' NC reaction was when rinsing the cotton, and as the sulfuric acid would get hot from the sudden addition of water, occasionally a hotspot would develop causing a sudden eruption of red gas. Anyway, I determined they were all white, and cold, so I figured I'd squeeze them out and place them in my bicarbonate solution. However, as I squeezed them a substantial part of it started burning! Very slowly, as it was wet, but wow... talk about unexpected! I'd hate to imagine what would happen if it had all gone up- 15g in my hand would be no good! I had allowed these to soak in the nitration bath for about 50 hours (I usually do 24, but work got in the way this time), perhaps that batch of NC was highly nitrated?

Not only do shotguns develop lower pressure, when firing blanks it'd be pretty hard to develop enough to split the barrel, unless it were to actually detonate, I think. I haven't gotten to firing a shell with shot loaded into it yet, but I'm looking forward to it.

The powder I've always used was in the form of disc-shaped flakes. I was thinking of making something is used for extruding pasta or play-do, but with tiny holes. I would then press through just enough for one flake through each hole, and run a blade across, cutting a couple dozen flakes per pass. It'd be slow going at first, but once I'm satisfied with what I'm getting, it won't be hard to automate it somewhat. I've sort of started, actually. I have a piece of pipe with a flat sheet of metal welted to the end that I drilled 10 small holes through. The other end is threaded on the outside, and I have a cap that screws onto it. In the center of that cap I drilled a hole and welded a 3/4" nut over that hole. I have a length of threaded rod that I can turn into that nut, and on the end of that rod is welded a 1/4" stainless circle cut to fit the pipe very carefully. It's a snug fit, so it's hard to get it in at first, it's gotta be very straight. I'm looking for a way to loosen that up a bit and have a bit of rubber or something around the edges to make for a better seal. I just made it yesterday so I haven't had a chance to try it out yet, but my plan is to determine how far to turn the threaded rod to extrude just enough material to make a flake of the proper thickness. I think that as it is it's going to be too hard to control like that unless I have a really long handle and have a dial of some sort with markings for each point to turn it to.

The idea was to have a razor blade cut the flakes as they're made automatically, but I haven't worked out how I want that to work. I was thinking of using an electric motor, but I seems like it'd be hard to mount. Instead I'm thinking know that I'll come up with a way to have a sort of guillotine chop, I know how I'll rig that up and it'll be sturdier than a spinning blade, liable to be bumped and knocked out of the perfect position necessary. Sorry for the long post, I spent a lot of time working on this last night and I'm hopeful that it'll work. And if it doesn't, oh well, there's nothing fancy or complicated about it, and it cost me less than twenty bucks to make (I'm guessing, I had most of the stuff lying around), but it should give me the ability to regulate the grain size with far more precision if it does. That'll make me a lot more comfortable firing full loads. I'm looking forward to taking my first rabbit with home made powder (maybe I'll make some shot, too. just about the only thing I can't really make is the shell itself and the primer).

Bert - 6-2-2015 at 07:24

Quote:

The only time I've ever had a 'runaway' NC reaction was when rinsing the cotton, and as the sulfuric acid would get hot from the sudden addition of water, occasionally a hotspot would develop causing a sudden eruption of red gas. Anyway, I determined they were all white, and cold, so I figured I'd squeeze them out and place them in my bicarbonate solution. However, as I squeezed them a substantial part of it started burning!

In NC plants, removing spent acid was done in a centrifugal wringer- A spinning mesh basket, similar to a washing machine drum on "extract". They caught fire fairly often...

Wringing and Drowning Theory

Quote:

It has been experimentally demonstrated that a 20 pound high grade linters dipping pot charge may be safely wrung as long as the acid retention is never reduced below 0.7 pounds of total acid (HNO3 ± H2SO4 ± H20) per pound of nitrocellulose.

Remove too much of the spent nitrating mixture before drowning the charge in water, you may have a fire.

I must tell you, your assumption of greater safety in using a shotgun for testing is just that- an assumption. Plenty of shotguns were destroyed in the early days of smokeless and semi smokeless powder development. We have better metallurgy for the most part now, but I would not be assuming ANYTHING (or holding a test gun in my hands).

I have a dead tree copy of this- It is from the early development period, and mentions slight changes in powder manufacture leading to damages. Don't have time to dig out page # & exact quotes right now.

http://archive.org/stream/gunitsdevelopmen00greerich/gunitsd...

In addition to cut or punched "flakes", early "bulk" shotgun powders were sometimes made by tumbling the chopped NC fibers (& sometimes other powdered ingredients) in a revolving "sweetie drum" and spraying the tumbling NC fibers lightly with a solvent that could gelatinize the NC. Eventually, the solvent droplets would stick fibers together into little clumps, and they would end up with a bunch of what looked like fuzzy tiny snowballs of NC fibers stuck together. For even faster burning (blank powder), a waterborne adhesive that did not gelatinize the NC at all could be used with very high % NC.

These powders were designed to be loaded with the same size scoop or whatever other volume measures had been used with black powder shotgun shells, rather than by weight, hence the name "bulk powder". They were low density, not very durable in handling, and tended to be very fast burning- These absolutely DID damage guns with fairly minor changes in % Nitrogen of the NC used.

Historical interest only, unless you want to duplicate "EC blank powder", perhaps. Note that the grenade fuze shown below with the smokeless powder filler has no blasting cap, but instead a black powder igniter charge. Loaded behind a projectile, it may turn a gun into a grenade.

Quote:

To fully develop the MK II into what most of us know today, another step was necessary. In the Basic Field Manual , Volume III, Chapter 5, Instruction With Hand and Rifle Grenades, 1932, a new grenade was described In this item the body remained the same with 40 deep serration's (48 counting the fuze neck), a filler plug with the body painted yellow and the main bursting charge consisting of .74 ounce of E.C. blank fire smokeless powder. The designation of E.C. indicated the proprietary compound first made by The Explosive Company seen in blank rifle cartridges.

Hatcher's Notebook: Notes On Gunpowder

https://books.google.com/books?id=yESNUKSg5aMC&pg=PA314&...

[Edited on 7-2-2015 by Bert]

[Edited on 7-2-2015 by Bert]

Hennig Brand - 6-2-2015 at 07:42

The nitration of cellulose is an equilibrium reaction, so to prevent loss of nitrogen content the acid on the NC needs to be diluted as quickly as possible. I use a large beaker of very cold water into which the NC, one cotton ball sized piece at a time, is plunged and agitate very vigorously with a glass stirring rod. The acid needs to be diluted as quickly as possible. This prevents hot spots and oxidation from the heat of dilution from occurring and also prevents any significant loss of nitrogen from occurring due to a partial reversal of the esterification reaction.

Interesting, good luck with your project. I was doing some thinking last night as well about how to make more regular propellant grains and I came up with a few ideas. If you look at the microscope pictures I took of my propellant, the flakes are very irregular. I was thinking of using moulds of known area that the propellant could be poured into before the solvent was evaporated. For a given mass of propellant this would be a more precise way of controlling flake thickness than trying to control viscosity by adjusting the amount of solvent. After most of the solvent had evaporated a cutter, much like a cookie cutter, with many parallel blades could be pressed down onto the sheet of propellant which would cut it into even strips. The cutter would simply need to be turned 90 degrees and the strips cut crosswise to make perfect flakes. If it took a lot of force, such as if a big sheet of propellant and large cutter were used, a press could be used to force the cutter through the propellant sheet.

[Edited on 6-2-2015 by Hennig Brand]

Bert - 6-2-2015 at 09:49

For your consideration:

Fred Olsen's MIT Bachelor's thesis: On the Gelation of Nitrocellulose

(see an overview of the graining process p. 55. How it was done, lots of nice little tech details)

https://dspace.mit.edu/bitstream/handle/1721.1/72784/3476445...

The historic rolling, punching, cutting & extrusion methods certainly work, and they are still used today for many products. I suspect they are made on some very durable legacy equipment, possibly older than many of the people running the presses.

Ball or flattened ball powders are very popular since the 1930's...

I am very lazy, and kind of like the idea of using a magnetic stirring hot plate and a beaker to try a small batch? So much less equipment to fabricate/bodge up. With Fred's description of using various electrolytes in the liquid to control droplet size, one might even get grains of a desired size to form themselves, after a bit of practice.

Solvents used could be ethyl acetate and water, for a first try. KleenStrip sold technical ethyl acetate as "MEK replacement" until last year, I have seen it on the shelves in some stores as recently as last month.

Afterwards, maybe one could run the grains through a warm roller to flatten if it seems necessary to even out or speed up burn.

Bert - 6-2-2015 at 14:02

Deterrant coating method for STRANDS of triple based powder, where a water bath application would leach out the water soluble nitroguanidine- Typicaly, strands coated before chopping into grains, and central core of resulting tubular grains NOT coated. The description of prior art in deterrant coatings, solvents etc. is of interest.

http://patentimages.storage.googleapis.com/pdfs/US4300961.pd...

Hennig Brand - 7-2-2015 at 08:06

Interesting finds, thanks. I am kind of interested in using DNT as a deterrent coating now.

I have seen the following propellants overview page many times before as it often comes up when doing Google searches of propellants and such. I decided to make a pdf of it and attach it here, since it has a lot of good information about advances in gun propellant technology during the first half of last century.

http://www.navweaps.com/index_tech/tech-100.htm

Attachment: Naval Propellants - A Brief Overview.pdf (196kB)
This file has been downloaded 1436 times

PHILOU Zrealone - 7-2-2015 at 11:25

H2N-NH-CO-N=N-CO-NH-NH2 is a good idea!

One step further ...
Polymeric (-NH-NH-CO-)n (poly-carbonyl-hydrazin) would not be bad too... just as the oxydized version (-N=N-CO-)n (poly diazo-carbonyle).

In a way to increase density further oxalyl variant (-NH-NH-CO-CO-)n and (-N=N-CO-CO-)n.

Bert - 7-2-2015 at 12:08

Thanks for the suggestions, PHILOU-

You generally need a solvent for applying these, I have read that DMSO dissolves azodicarbonamide, and that it will precipitate from DMSO solution on contact with water.

I ASSUME DMSO would carry the substance past the surface of the grains and into the interior as well, depending on dwell time before contacting a water rinse.

Can you suggest solvents for your proposed materials?

Bert - 7-2-2015 at 12:14

Does anyone want this thread stickied?

And maybe change of title to "propellants and powders: single, double and triple base"

Or suggest any other suitable titles?

Hennig Brand - 7-2-2015 at 13:29

I think it should be stickied. It is turning into a great thread.

The following copy/paste is from, "High Energy Materials: Propellants, Explosives and Pyrotechnics" by Jai Prakash Agrawal (pg. 227). Notice how DNT is listed as a propellant coolant as well as a surface moderant.

"4.8
Ingredients of Gun Propellants
The gun propellant formulation usually contains one or more energetic compounds
as main ingredients. In addition, it includes minor quantities of plasticizer,
stabilizer, inorganic salt, surface moderant, ignition improving agent, flash
reducing agent, decoppering agent, gun wear reducing agent etc. Some important
ingredients are:
• Energetic compounds: NC, NG, picrite, RDX etc.
• Plasticizers: phthalate esters (DEP, DBP, DOP), TA, NG, liquid nitro/azido
compounds etc.
• Stabilizers: DPA, carbamite, methyl centralite, 2NDPA etc.
• Coolants: dinitrotoluene (DNT), TNT, carbamite, mineral jelly etc.
• Flash reducing agents: K2SO4, cryolite, potassium nitrate etc.
• Inorganic salts: CaCO3 . MgO etc.
• Ignition improvement compounds: Ba(NO3)2 , KNO3 , camphor, carbon
black etc.
• Surface moderants: carbamite, camphor, DNT, methyl centralite etc."

There are other texts too giving similar descriptions for how DNT is used in propellants. Some texts list DNT as a propellant plasticizer as well. It would seem that DNT can be incorporated into the main propellant mixture, not just on the surface as a deterrent but, also for the purposes of cooling the propellant and as a plasticizer. It seems like DNT has had extensive use for these purposes.

Quite a few materials seem to be effective for cooling a propellant, even inert materials, however nitroguanidine would likely be very effective at cooling and sacrifice less in performance than most, or all, of the other choices. Nitroguanidine would usually win in terms of nitrogen production, as well, which is another big advantage for reducing barrel erosion. Personally I hope to find that DNT works reasonably well and helps make serviceable rifle propellants. Obtaining cutting edge performance with expensive/exotic materials is probably not where I am at in my quest for homemade propellants. Being able to use readily available or easily made materials is very exciting though.

[Edited on 8-2-2015 by Hennig Brand]

Bert - 7-2-2015 at 13:39

And FedEx will ship 2,4 DNT to me (ground freight only). Thank you, FedEx...

Hennig Brand - 8-2-2015 at 11:24

The following was taken from "TM 9-1900, Ammunition, General" 1942 edition (pg. 33). The way it is stated is a bit open to interpretation, but it looks as though perforations were considered of much less importance for cylindrical small arms propellants (.30 cal. for example) than for cylindrical propellant for large guns.

"17. SMOKELESS POWDER.

a. Characteristics: Smokeless powder is essentially gelatinized
nitrocellulose and is manufactured in the form of flakes, strips, pellets,
or perforated cylindrical grains ( fig. 19). Powder is made in different
shapes to obtain certain types of burning (par. 17 c). The cylindrical
grains are made in various diameters and lengths. Grains vary in
diameter from 0.032 inch for caliber 30 cartridges to 0.947 inch for
16-inch propelling charges, and vary in corresponding lengths from
0.085 inch to 2.170 inches (fig. 20). For small-size grains either no
perforation or a single perforation is required. However, for larger
grains, seven equally spaced perforations are present in order to have
a large burning surface area (par. 17 e). The critical dimension is
the web size, that is, the average thickness of the powder between the
perforations. In color, the grains vary from a light amber to a deep
brown or black."

caterpillar - 8-2-2015 at 14:58

Digging in the Net, I found one interesting text (sorry, I cannot say now, where in particular- it seems to me that here, http://parazite.nn.fi/roguesci/index.php/f-7.html but I'm not sure). After this forewords, read this:

"
Back in the '90s, I worked for a refractory metals and high performance ceramics outfit down in LA. We got a subcontract from Saco Defense for a program to develop a cannon barrel that was resistant to the erosive effects of Nitramine-based propellants. One powder formulation in particular was especially destructive to bore liners (even stellite!), shooting-out the bores in about 75 rounds. This is not acceptable performance in an automatic weapon.

Most of these propellants contained more than 50% RDX. The mechanism contributing to the bore erosion had to do not so much with heat per se', but wth hot nitramine particles coming in contact with the interior surface. While the isochoric flame temperature was somewhere around 3,000 Kelvins, the surface temperature of the still- burning nitramine particles was somewhere above 4,000. These things were bouncing around inside the barrel like pinballs, at supersonic speeds, and wherever they impacted the bore surface it would scorch a little pit. so it didn't take long to wear down the forcing cone and rifling to the point where the barrel was unusable, spraying all over the range.

What we came up with, initially, was a subscale barrel in .50 BMG which, using the same propellant, lasted through a 10,000 round burst with no detectable wear. The guys at Saco and ARDEC thought we were God. They had tried every trick in the book, 718 alloy, hard chrome, Stellite, and nothing seemed to work.

What we came up with was a liner of pure Rhenium, CVDd on a sacrificial monolithic graphite mandel, with a 4340 chrome moly sleeve shrunk onto it. The graphite was then burned out with an Oxyacetylene torch, modified to extend down the bore. Soon, a few were made in 25 mm for the Bushmaster cannons on the Bradleys.

The "big barrels" cost $10,000 apiece, but were still a bargain when compared to the conventional barrels that cost two grand and wore out in less than 100 rounds. Why they never went into full production is hard to figure.

Anyway, you can expect similar problems if you try to make rocket nozzles out of conventional materials. Carbon-Carbon may hold up for a "one shot deal," but if you are shooting for a reloadable motor with a reusable nozzle, solid Rhenium is damned expensive. And if you're thinking about a Rhenium coating on a CC or graphite nozzle, forget it. We tried that shit (against my better judgement) with a hypergolic satellite positioning thruster, and it failed catastrophically at about 20 seconds of burn time, due to CTE mismatch.

For a gun propellant, though, the nitramine content provided about a 40% increase in muzzle velocity, which translated into about a 25% increase in KE downrange.

Good luck, intrepid scientist!"

Hennig Brand - 8-2-2015 at 15:43

Interesting post you found there. I found the following in, "Chemistry of High-Energy Materials" by Klapötke which is along the same lines as your post about triple base propellants with RDX. It seems that the person who made that post, at the old E&W forum, may have known a few things this author did not about the situation with nitramine propellants and barrel wear.

"To prevent erosion and the muzzle flash, a triple-base powder (NC + NG + NQ) with an NQ content of up to 50% is used, particularly in large calibre tank and NAVY weapons. However, the performance of triple-base powders is lower than that of double-base powders (Tab. 2.4). In a triple-base powder, particularly in large tank and NAVY cannons, NQ is replaced by RDX in order to increase the performance. However, the barrels suffer increased erosion problems again due to the significantly higher combustion temperatures."

Homemade Cord Propellant

I just recently ordered one of these:

http://www.ebay.com/itm/2014-Kitchen-Stainless-Steel-Pasta-N...

It is a cheapie, but it may do at least for experimental purposes. It comes with three spaghetti noodle dies; 1mm, 2mm and 3mm and the drum is 6cm in diameter. Hopefully I will be making cylindrical grains of propellant soon.

Noodle Press.png - 36kB

[Edited on 9-2-2015 by Hennig Brand]

Hennig Brand - 8-2-2015 at 19:53

DNT is used in fairly large quantities in some propellants (10% or more), that and the functions it performs made me think that maybe it is sometimes mixed in the bulk formulation with the NG and NC at the time of manufacture (before propellant grain formation). This was maybe an incorrect assumption, since apparently DNT applied to the surface of the grain travels by diffusion quite readily into the propellant grain creating a concentration gradient which helps regulate the burn rate. One of the big obstacles has been, or is still, to control this diffusion process. DNT is very miscible with NG and readily forms bonds with NC. It is possible that the DNT is only added after the propellant grains have been formed. So far I am not sure.

Trotsky - 9-2-2015 at 03:33

That's almost exactly what I made Hennig. Hopefully it'll work well. I'm not a big fan of spreading NC gel on a surface and trying to remove and cut it to shape.

I was experimenting with raw NC, NC plasticized with acetone and dried on a flat surface and extruded acetone plasticized NC, and controlling for weight, there is way more carbon left after burning the plasticized material than the raw stuff, and slightly more for the flat than the extruded flakes. There were air bubbles in the flat stuff not found in the extruded, which have to be removed before use, but perhaps they are part of the problem, maybe they were just smaller in the extruded stuff. Thoughts?

Hennig Brand - 9-2-2015 at 06:14

I may make an extrusion press yet, but for now the spaghetti press was only $15 delivered. The raw fibrous NC would burn more completely in the open because it has better access to the oxygen from the air (of course if you used solvent you still will have at least a small amount of solvent left in the gelatinized propellant as well which is added fuel). I found that pouring the gelatinized propellant out on a piece of wax paper to be extremely convenient actually. The sheet once mostly dry could be very easily peeled off and then put on a cutting board to be cut up with the rolling cutter. A mould to control the surface area of the sheet would likely be a good addition. The only problem was regulating particle shape and size which is why I am trying other things now. The geometry of cylindrical grains is better than flake for larger rifle also.

I haven't had a lot of trouble with air bubbles, but I can see how air bubbles could be added depending on the amount and type of mixing that was used. I usually just add the NC and solvent to a sealed polypropylene container and leave it overnight or longer to fully gelatinize, I then add the NG (if used) with slow careful mixing. If air bubbles need to be removed, the container of gelatinized propellant could be put under vacuum, while the solvent is still in and the propellant soft and with low viscosity, which should remove the bubbles.

[Edited on 9-2-2015 by Hennig Brand]

Trotsky - 9-2-2015 at 07:22

I guess I never tried letting it just sit in solvent, I've always constantly stirred it. It seems like sometimes bits of nc gelatinize on the outside and block access to the inside by the solvent, which is why I've always stirred it. I thought about applying vacuum when still wet with solvent, it'd be one way to enhance removal of solvent, but I think it'd ultimately decrease density, which may or may not be desirable. I wonder how they would effect the application of deterrent coatings or nitroguanidine after hardening.

I've not had much luck with cutting the extruding NC cords, unfortunately. It's tough to get the NC dry enough that it doesn't stick to everything and wet enough to still be workable.

The only thing I don't like about press-cutting the grains is the difficulty in making very many of them, it's a fairly labor costly method. I wanted to be able to run an ounce of propellant through my extruder cutting flakes in five to ten minutes.

My next though was maybe taking a sheet of Teflon of the desired thickness of my grains and drilling a hundred or so holes of the desired diameter through it, lay on a solid sheet of Teflon and then scrape the wet NC gel across it, working it into the holes, like putting putty in a nail hole. I think blowing it with a hair dryer for a few minutes would produce enough of a skin on the NC that the forming plate could be removed and used to make another set of grains.

Bert - 9-2-2015 at 07:33

From experience gained in making NC lacquers for pyrotechnic binder:

If you immerse either fibrous NC or most particularly finished NC powder in acetone, dissolution is slowed by the surface gelling and the solids chunking up- It can take a week or longer to dissolve a fairly small amount of factory made smokeless if you just pour acetone into a jar and let it sit.

If the solids are thoroughly wetted with ethanol, to the point where grains are an alcohol slurry and the acetone then added with stirring, the process goes a LOT faster.

Hennig Brand - 9-2-2015 at 12:35

Thanks Bert, that sounds like a good tip. Do you think that methanol could be substituted for the ethanol?

I guess I do stir some as well, but I wait until the fibrous NC has soaked in acetone for quite some time and has become very soft. I probably only stir for ten seconds or so, two or three times during the whole dissolution process. I wonder at this point if I am really getting everything dissolved as well as I should when using the long fibered, fibrous NC. MCNC dissolves much easier and forms translucent solutions with acetone. This could help explain why the densities of the propellants I made with regular long fibered NC were often so low.

Trotsky, I will need to wait until I try the extrusion method to make comparisons and provide some input. Should be fairly soon.

[Edited on 9-2-2015 by Hennig Brand]

Bert - 9-2-2015 at 13:08

I have never tried it with straight methanol, but a lot of the paint store solvent grade ethanol used was DENATURED with methanol AFAIK.

I note most ether/alcohol solvent systems for NC in older powder making processes specify ethanol- Don't know if it was solubility or economics driving that choice.

Hennig Brand - 10-2-2015 at 04:37

Just wanted to point out that the DNT used in propellant formulations is not normally pure 2,4 DNT even when it is decribed as such in some cases. Apparently it is normally a mix of DNT isomers with the largest proportion being 2,4 DNT. I have seen several references indicating this in the last week or so, but I didn't think to make a note of them at the time.

Trotsky - 10-2-2015 at 20:01

How is the flake commonly used in shotguns produced commercially? It looks like it must be incredibly thinly sliced extruded cord, but I can't figure out how they can process it. When it's still relatively wet it's far too sticky to cut that thinly- it's easy to extrude cord, but trying to process it that thinly into paper thin flakes is inconceivable to me at this point. Once the cord is dry it's damn near impossible to process it at all.

Obviously there is a process out there, but I can't think of it.

I have spread it in a thin sheet, cut it into .25in x .25in squares, allowed it to finish drying before, but it's performance in a shotgun is not nearly good enough. It's too slowly burning to develop enough pressure to fire shot at a reasonable velocity. It's also not cleanly burning enough.

I know most shotgun powders are double base, so maybe I should give up trying to make a single base propellant work well enough.

I don't have experience trying to process a double base powder. Are my problems processing it into flakes because I'm working with just NC and not blending with NG? I would think that a double base propellant would be easier to work with, once the solvent had evaporated I would think that the NG would keep the now plasticized NC softer and more easily worked. Is there a point when drying that say an 18% NG double base would be soft enough to cut finely but stiff enough that it wouldn't deform and stick to everything? I work somewhere where we do a good bit of extrusion, so I'm pretty familiar with a number of industrial extrusion techniques. Our end products are vastly different, but from what I can tell the actual techniques are pretty similar, it's the post extrusion processing that's completely different. I'm sure when these guys were originally working out the process they had a lot of raw materials to spend on developing their method so they had the flexibility to make changes on the fly until they had something that worked, and once they were that far they could simply make small changes to dial the process in to yield a better product in various aspects and to increase their throughputs.

Whatever process they were going to use had to be one that could be easily scaled up to pump out serious poundage. I don't know what sort of pounds per hour these plants are expected to produce, but where I am I think the lowest we do for anything (well, lowest accepted, there are always times when machinery doesn't cooperate to hit standards) is 1800lbs/hr, but virtually everything else is 3-4k though there are some we can run a bit over 9k. I wouldn't expect these places to pump out volumes like that because of the difficulty in producing tens of thousands of pounds of nitrocellulose that would be needed each day, but I would imagine they do at least a thousand pounds per hour, it'd be hard to make a profit with less, powder isn't very expensive after all, and the people producing it can't be cheap labor- you're not going to be paying the guy working with large quantities of nitrocellulose and nitroglycerin 10 bucks an hour, I can only imagine the press's reaction if there were an accident and they found out the plant was under paying employees. That would be a fun job to have!

I wonder if there are any 'How it's made' sort of shows on YouTube showing smokeless powder manufacture. They'd probably be rather vague about details for obvious reasons, but I could glean a lot of information just by seeing the process based.

Hennig Brand - 11-2-2015 at 04:25

The flakes are likely passed through one or more sets of rollers to flatten them out to their final thickness. Double base propellants are much easier to work with, or so I have found, since the NG acts as a plasticizer/softener. Plasticizers are often added to propellants with one of the main reasons being to make processing easier or possible. Also, vibration might work well to remove air bubbles from the propellant before the solvent is removed. I have found the same thing too; information found is often not very specific with regards to propellant manufacture.

aj_hazem - 18-2-2015 at 13:05

Double base and single base propellants are plastic like material witch mean that you need heat and pressure to give it the proper grain size and shape.
The best practice is to use a twin screw extruder, single screw extruder give inferior quality for the final product.
The using of a solvent help improve the Workability.
Solvents include ketones like acetone and include ethyl acetate, diethyl ether/ethanol the solvent used mostly in industrially is the later.
There is two other methods one for making sheet like propellants, stripes or rings. And the other for making ball powder which uses an emulsion in inert (water) carrier.

[Edited on 18-2-2015 by aj_hazem]

Need manufacturing details

aj_hazem - 18-2-2015 at 13:22

Quote: Originally posted by specialactivitieSK

Smokeless rocket propellant :

DEGDN : 45 %
NC /12,5%/ : 53 %

[Edited on 28-10-2014 by specialactivitieSK]

Can u please describe the methods used in making that propellant grain the rocket propellant i mean.

Trotsky - 19-2-2015 at 01:10

Yeah I'm familiar with extruder tech, and it seems obvious to me how they make many types, but are these perfectly round flakes, identical in size, coming from thin sheets and punched, or extruded through holes and cut? In my industry we mostly do the latter, but we don't work with anything that tiny.

woelen - 19-2-2015 at 07:58

@aj_hazem: This is the third time that you ask for practical information, useful for weaponizing certain compositions without actually showing any interest in the science behind these things. What are you up to? Bert already put two of your threads about construction of hand-grenades in detritus and this latter part of this thread could easily end up there as well, together with your account.

Discussing energetic materials is fine, but wo do not want the discussion going towards weaponizing these things.

aj_hazem - 21-2-2015 at 10:45

Coin-like shaped ballistite ( smokeless powder) are manufactered from ball powder patented by olsen in 1919 if i my memory is still working well , the patent describes making an emulsion of NC in ethyl acetate in water with strach then slowly evaporating the solvent while agitation is continued ,small spheres starts to appears and case hardened.
After that the ball is smashed between hot cylinder (roll mill).

aj_hazem - 21-2-2015 at 10:58

Quote: Originally posted by woelen

@aj_hazem: This is the third time that you ask for practical information, useful for weaponizing certain compositions without actually showing any interest in the science behind these things. What are you up to? Bert already put two of your threads about construction of hand-grenades in detritus and this latter part of this thread could easily end up there as well, together with your account.

Discussing energetic materials is fine, but wo do not want the discussion going towards weaponizing these things.

You're an admin you can simply delete my post or even ban me from ever posting. The thing is that i'm already up to make solid grains but i'm facing the problem of residual solvent remaining traped inside the grain.
I think it's sciences not weaponizing some thing cuz i'm not asking you to give me practical details on rocket systems. Man you are using a twisted logic here.

aj_hazem - 21-2-2015 at 11:15

I guess bullet are a projectile fired for weapons!
Shaped charge are devices invented to penetrate steel targets, oil wells and armored car!
Correct me if I'm wrong!

Hennig Brand - 21-2-2015 at 17:32

There is no point and no need of being offended. Anyone who came new to this forum and asked for help to build a grenade would have had the same treatment, would have drawn attention to themselves and be looked at with suspicion afterwards for at least a while. Actually, Bert and Woelen have been incredibly polite about the whole thing (I checked the posts myself). It often depends how things are discussed and what kind of track record the member has I think. What is appropriate can often be somewhat subjective, but in your case it was very clearly very much against forum rules.

Trotsky - 25-2-2015 at 23:30

Hennig, have you experimented with taking acetone-colloided NC (1% Vaseline, <.5% sodium carbonate) and adding it back to water? I hadn't tried it before, though I had read that it returned the gel to an almost cotton-y like state, so I gave it a shot. It does turn similar to cotton, I suppose, in a way, but as it dries it's easily turned to a fibrous powder. This material doesn't start as a powder exactly, instead as a fibrous chunk of the stuff, but as you slowly work it between your fingers, it turns to a fibery powder.This material might be useful as a powder in a .22, I'm not sure yet. It seems like it's reproducible and pretty homogenous. Particle size is a bit smaller than I want for a shotgun powder, unfortunately, but it seems pretty close to what I'd want for a .22.

I'm not particularly fond of pressing in sheets and cutting it. While it's not hard to get particle dimensions right (though highly tedious), it is very difficult getting the sheets proper thickness. It seems that commercial flake powders have the thickness of the plastic film that I remove from my glassware after the NC gel that I couldn't remove dries on it.

Also, are your NC flakes orange-ish in color? Why is that? Once I add it back to water to make the fibrous powder described above it turns back white, but let it dry in a sheet of any sort of thickness and it's opaque orange-ish.

Or are you getting your sheets thin enough to end up transparent? That's real thin, but I haven't gotten or really tried to get, sheets that thin.

I'm going to do some more experimentation with turning it back to a fibrous nature by adding it back to water. There are a lot of really tiny particles produced that are too small to be used, but if properly classified, the primary size I obtained in my first attempt with it was actually good.

I have done a lot of testing, comparing burn rates and such compared to commercial powders, and comparing the "poof" obtained burning a single "average sized" particle to a single flake of commercial powder is very similar, and video comparison of the little fireball produced is almost identical. This is done using a pre-heated hot plate onto which particles are dropped, or placed onto the hot plate and heated until they ignite. I need to prepare another batch of this sort of material to test burn rates on larger sample sizes, ie: compare burn rates of 100mg and 500mg of my 'fibrocellulose' (I dunno what else to call it) to commercial smokeless powders. I'm thinking that it's going to be very similar based on my early tests. After that I need to come up with a way to measure burn rates under some sort of pressurized condition. Not sure how to do that as an amateur yet. Easy to do, but measuring it accurately isn't. Film and watch in slow motion, maybe?

Hennig Brand - 28-2-2015 at 09:14

No, I haven't tried that. Fibrous propellants, as apposed to colloided propellants, normally produce higher pressures and are much more prone to accelerate even to detonation when confined and ignited. In comparison to most other calibers, I think you can get away with a lot more with a .22 in terms of unideal propellants and still get reasonable results and no disaster, but I would still be cautious.

Once you have determined the density of your finished propellant, it is easy to control the thickness by controlling the other two dimensions (size/area of sheet). An easy way to do this would be using a mould, of appropriate dimensions, that the gelatinized propellant can be poured out into.

The sulfuric acid I use for nitrations has orange colored dye in it and the fertilizer grade ammonium nitrate also has impurities that can impart a yellowish color. My NG and NC are often colored a yellowish orange color because of this, however even using pure acids NC in particular can have a yellowish tint to it, depending on the level of nitration and how it was processed.

From what I have seen and read, the performance of smokeless propellants based on NC or NC & NG is extremely predictable if the composition can be controlled and the particle size and shape controlled. With the exception of long range marksmanship where each round must perform as close to exactly the same as the last as possible, it is much easier than we have been led to believe to produce serviceable propellants (in my opinion). Extremely precise propellants, as are used for getting consistent results for 1000 yard shots for instance, would take much greater attention to detail. It seems like as with a lot of other things, we can get 80 or 90% of the way there with maybe half or less of the effort.

[Edited on 1-3-2015 by Hennig Brand]

Trotsky - 28-2-2015 at 11:14

take a little thick NC-acetone and add it to 70% isopropanol, squish it around a little bit until it's entirely not sticky. I've found that the isopropanol works a little better than plain water. Once it's good, take it out, use a rolling pin and press it as flat as possible. Let it dry, break it up a bit and stack it into a pile, then cut into small pieces with a knife. I just keep cutting it as small as I can, then I kind of roll it between my fingers until it breaks about as fine as I can get it.

It's not truly fibrous but it sort of is, too.

This burns as close to commercial powder as I've gotten to date.

Hennig Brand - 1-3-2015 at 01:07

What you said about needing to test the burn rate under some sort of pressurized condition is important. I am not sure how much useful information can be had from measuring the burn rate of unconfined smokeless propellants.

The following was taken from "Ammunition General" (TM 9-1900):

"
Burning Action.

Unconfined nitrocellulose propellant burns relatively slowly and smoothly but, when confined, its rate of burning increases with temperature and pressure. In order not to exceed the permissible chamber pressure of the weapon in which it is to be used, the rate of burning of the propellant has to be controlled. At any given pressure, the rate of burning is proportional to the propellant surface free to burn. Therefore, propellants are made into accurate sizes and definite shapes."

Stabilizers: Diphenylamine and Centralite

Hennig Brand - 19-3-2015 at 12:10

I have seen references which indicate that diphenylamine causes hydrolysis of NG and that for double base propellants centralite, typically ethyl or methyl centralite, is recommended instead. However, I have also seen that double based formulations do often contain diphenylamine and sometimes diphenylamine and centralite. I now have 500g of diphenylamine, but it looks as though centralite might be more appropriate for double based propellants. From my experience double base propellants are much cheaper and easier to make than single based and more powerful as well. I can attach some references shortly.

From "Military Explosives":

"
9-12. Stability. The stability of nitrocellulose, which
was discussed in Chapter 8, is relatively poor. The
stability of nitrocellulose based propellants is
correspondingly poor. The degradation of nitrocellulose
proceeds by two chemical reactions. In the first
degradation reaction, nitrocellulose loses nitrogen
oxides. The loss of nitrogen oxides an intrinsic tendency of the nitrocellulose molecule.

The reaction rate varies with the temperature, but even
at low temperatures the loss of nitrogen oxides occurs.
In the second degradation reaction, which occurs initially
as a result of the first, the nitrogen oxides that are
formed attack the nitrocellulose molecule. The reaction
between the nitrocellulose and nitrogen oxides produces
more nitrogen oxides. The increased number of
nitrogen oxides and increased temperature cause the
reaction rate to accelerate. After a few years the
reaction rate in samples of sufficient size is so fast that
the propellant self-heats above the flame point and will
self-ignite. Nothing can be done to stop the first
degradation reaction. The second degradation reaction
is controlled by two means. The heat of reaction is
dissipated by a suitable heat sink, for example the metal
case of a cartridge is an excellent thermal conductor.
This does not solve the problem totally, however, if the
diameter of the cartridge case exceeds 3 inches. The
second, and most effective, means of controlling the
degradation reaction is to include a chemical stabilizer
in the propellant composition. A stabilizer has a greater
affinity for the nitrogen oxides than nitrocellulose, and
so absorbs them before they can attack the
nitrocellulose molecule. This reduces the rate of
propellant decomposition to about that of the first
degradation reaction. However, the stabilizer is
consumed as it absorbs nitrogen oxides. Therefore the
increase in time the propellant will remain stable is
directly proportional to the amount of stabilizer added.
Some propellants can be stabilized in this manner for 30
or 40 years. Three stabilizers are of interest for military
applications in the United States; diphenylamine (DPA),
ethyl centralite (EC), and the akardites (AK). DPA is
used in single-base propellants but is incompatible with
nitroglycerin and so cannot be used in double-base and
triple-base compositions. EC or 2-NDPA is used for
double and triple-base propellants which use
nitroglycerin as the gelatinizing agent for the
nitrocellulose. Akardites are used in propellants that
contain DEGN rather than nitroglycerin.

a. Diphenylamine, (C6H5)2NH, is an ammonia
derivative in which two of the hydrogens have been
replaced by phenyl groups. Each phenyl ring has three
hydrogens which can be replaced with nitro groups.
Therefore, DPA can be nitrated to the hexanitrate by
absorbing the nitrogen oxides produced during the
decomposition of nitrocellulose. DPA is nitrated
relatively easily and the reaction is not exothermic.
During the decomposition of nitrocellulose, DPA nitrates
to the following compounds in succession.

N-nitrosodiphenylamine
2-nitrodiphenylamine
4-nitrodiphenylamine
N-nitroso-2-nitrodiphenylamine
N-nitroso-4-nitrodiphenylamine
4,4', 2,4', 2,2', and 2,4-dinitrodiphenylamines
N-nitroso-4, 4'-dinitrodiphenylamine
N-nitroso-2, 4'-dinitrodiphenylamine
2, 4, 4' and 2, 2', 4-trinitrodiphenylamines
2,2', 4,4'-tetranitrodiphenylamine
2,2', 4,4', 6-pentanitrodiphenylamine
Hexanitrodiphenylamine

The propellant does not start to become unstable until
most of the diphenylamine has been converted to
hexanitrodiphenylamines. A very accurate test to
measure the remaining safe storage life in a propellant
lot is to analyze the distribution profile of the nitro DPAs.
Only about one percent DPA can be added to a
propellant because its nitrated products change the
ballistic properties.

b. Centralite I (which is also called ethyl centralite
or symmetrical diethyldiphenylurea), OC [N-(C2H5)
(C6H5)]2, was developed in Germany for use in double
base propellants. The compound acts as a stabilizer,
gelatinizer, and waterproofing agent. Unlike
diphenylamine, centralite can be used in relatively large
proportions and some propellant compositions contain
as much as eight percent of this material. Like
diphenylamine, centralite is nitrated by the products of
nitrocellulose decomposition. The following compounds
are formed successively, as many as four being present
simultaneously, as deterioration of the powder proceeds.

4-nitrocentralite
4,4' dinitrocentralite
N-nitroso-N-ethylaniline
N-nitroso-N-ethyl-4-nitraniline
2,4, dinitro-N-ethyl-aniline

Centralite II (which is also called methyl centralite or
symmetrical dimethyl diphenylurea), OC[N(CH3) (C6H5)
]2, also has been used as a stabilizer but is not
considered to be as effective as the ethyl analogue.

9-4. Akardite II is often used in DEGN containing
propellants. c. Three akardites, or acardites, are used to
stabilize propellants. Their structure is shown in figure 9-4. Akardite II is often used in DEGN containing
propellants."

There are many other references as well discouraging the use of diphenylamine in double base propellants, but also some sources suggesting it as well.

[Edited on 20-3-2015 by Hennig Brand]

Hennig Brand - 26-3-2015 at 09:05

I recently posted the following on page forty of the shaped charge thread. It is probably even more relevant in this thread, so I have included it here.

Quote: Originally posted by Hennig Brand

To act as a chemical stabilizer, making the explosive more storage stable. It does also desensitize the explosive to initiation a lot as well, but that was not what I was commenting on. The following was taken from the Naval Propellants page which has a pdf made of it in the propellants thread, "Mark I cordite consisted of 37% nitrocellulose (13.1% Nitrogen), 58% nitroglycerine and 5% petroleum jelly. This last ingredient had originally been used as a lubricant during the manufacturing process, but it was found that it also acted as a stabilizer as its unsaturated hydrocarbons counteracted the byproducts of the decomposition process."

I wonder if the Vaseline we buy at the drug store is the same as what they were using to make Cordite. Has it been purified and the unsaturated hydrocarbons been removed for the most part?

Here is something else of interest, taken from an old defense document (Powder and Explosives by A. G. Gorst). Comparing the heats of explosion, it is very clear why double base propellants are normally so much more powerful than single base propellants and also why double base propellants typically damage barrels at a much higher rate as well.

Heat of Explosion of Nitrocellulose and NG.jpg - 66kB

[Edited on 26-3-2015 by Hennig Brand]

Bert - 1-11-2015 at 07:15

In at least one place, the manufacture of improvised powder IS regularly done: Khyber pass!

http://www.rimfirecentral.com/forums/showthread.php?p=518568...

Found this posted by a Pakistani of another forum I'm a member of, with pictures of re-manufactured 7.62X39 rounds using spent cases with home made bullet, primer and POWDER. They are NOT careful reloaders nor accomplished powder makers...

[Edited on 1-11-2015 by Bert]

greenlight - 1-11-2015 at 08:33

What sort of homemade propellant is that? Looks like chopped up tobacco.

Aren't the grains to reload rounds supposed to be of uniform size and shape for loading the correct amounts and for burn rate control? Those look to be of all sizes and shapes.

[Edited on 1-11-2015 by greenlight]

Fulmen - 1-11-2015 at 14:02

Although I'm sure it's beneficial, absolute uniformity isn't required as long as it's bulk uniform (meaning that two charges will have approximately the same size distribution). Regular black powder is like this, it's powder that passes one mesh and is retained by another. And the range can be pretty large for certain powders.

Bert - 1-11-2015 at 16:51

If one reads the whole thread linked, it is obvious that uniform ballistics (or personal safety of the end users) is not achieved by this manufacturer!

Different loaded weights, no or very little grain size control, local gunsmith testifies that he sees lots of destroyed weapons due to the ammunition... That the ammo was not "Russian surplus" was discovered AFTER the users had frequent problems.

I suspect either this propellant was manufactured much as some of the "pizza cutter" grains earlier in this thread, or perhaps it may even be broken up high explosive shell filler, mining explosives or something else cheap, explosive and equally inappropriate that was to hand up by the Khyber Pass.

The OP of that thread did post a video of burning factory 7.62x39 stick powder and a sample of this "weed" powder as he names it. The burn rate of the improvised powder is way faster.

http://vid1270.photobucket.com/albums/jj613/zainulabdeen/IMG...

http://vid1270.photobucket.com/albums/jj613/zainulabdeen/fak...

I did ask some questions, but the original poster has some more pressing business of late. Staying alive, primarily. He's a government official in Pakistan, and some locals recently decided he needed to be abducted/murdered.

Be glad, those of you who live where propellant chemistry is an amusing hobby.

[Edited on 2-11-2015 by Bert]

James Ikanov - 13-11-2015 at 11:56

Hopefully one might forgive my laziness for not reading the bulk of this thread, but one thing I've recently read about in another forum is specifically ball powder.

https://en.wikipedia.org/wiki/Ball_propellant#Constituents

The wikipedia article on it offers some surprisingly specific details and it sounds plausible that some variety of it could be made with some difficulty at a hobbyist scale.

Perhaps a simple sealed container with two valves and a cap of some kind (cap for pouring in the syrup and all the additives, one valve for raising pressure, and one valve for slow venting) mounted onto something like a ceramicists stand could be used to induce the formation of the individual balls?

Not a very simple proposition, but I think it could be done with a bit of effort.

Edit: Oh, bother, it seems this may have already been mentioned.

[Edited on 13-11-2015 by James Ikanov]

Hennig Brand - 20-3-2016 at 09:22

Bert I know you are trying to keep people safe, so I will start by saying that much I respect. I am a little tired, however, of a world where in an attempt at complete safety so much of the good things have been taken away and even a great many lies are told.

Quote: Originally posted by Bert

If one reads the whole thread linked, it is obvious that uniform ballistics (or personal safety of the end users) is not achieved by this manufacturer!

Different loaded weights, no or very little grain size control, local gunsmith testifies that he sees lots of destroyed weapons due to the ammunition... That the ammo was not "Russian surplus" was discovered AFTER the users had frequent problems.

I suspect either this propellant was manufactured much as some of the "pizza cutter" grains earlier in this thread, or perhaps it may even be broken up high explosive shell filler, mining explosives or something else cheap, explosive and equally inappropriate that was to hand up by the Khyber Pass.

The OP of that thread did post a video of burning factory 7.62x39 stick powder and a sample of this "weed" powder as he names it. The burn rate of the improvised powder is way faster.

http://vid1270.photobucket.com/albums/jj613/zainulabdeen/IMG...

http://vid1270.photobucket.com/albums/jj613/zainulabdeen/fak...

I did ask some questions, but the original poster has some more pressing business of late. Staying alive, primarily. He's a government official in Pakistan, and some locals recently decided he needed to be abducted/murdered.

Be glad, those of you who live where propellant chemistry is an amusing hobby.

[Edited on 2-11-2015 by Bert]

I haven't spent much time reading this thread since I took a break from propellant research and experimentation. The last few posts needed some discussion some time ago.

Bert posted the following link on the last page of this thread, which showed pictures and discussed damage done by what was described as homemade propellant in Pakistan.

http://www.rimfirecentral.com/forums/showthread.php?p=518568...

I am a bit insulted actually to be compared to this. I did good research I think and was honest about the limitations and shortcomings of the propellants I made. We know very little actually about what these Pakistani loaders/reloaders were using for propellant. We do know by looking at the first few pictures that they couldn't even be bothered to make the loads even approximately consistent in weight which means that scales were likely not used at all when loading, which is actually the easy part, so what does that likely say about everything else done by them.(?) Although the grain size and shape actually don't look terrible to me, the huge variance in color between many of the grains suggests to me that the composition is likely not consistent as well (poor mixing or different materials altogether in different grains?).

Without intentionally trying to be inflammatory, I have to say that it is true I know only a little about reloading, but I do know about basic physics/ballistics and chemistry and engineering. I have also known many people who spent a lifetime shooting rifle and handgun as a sport and who reloaded and most actually knew very very little about the science of propellant manufacture from what I saw. They knew how to consult a reloading manual and read the numbers off the bottles of propellant and use the reloading equipment for the most part. Many also knew a lot about spreading old wives tales about drops of NG falling to the ground and leveling a whole building and about how dangerous and impossible it is to make ones own propellant. Most people, even those who use guns a lot, don't look objectively into propellant manufacture in much depth! It is an obscure topic, with at least 1000x more false, or at least very vague, information floating around than good information.

Points to consider for the homemade propellant in this thread:

1. Greater efforts should be put into making a more suitable grain type (cylindrical rather than flake probably), with consistent particle size, especially if it will be used in large rifle. At the very least flake size should be consistent and of suitable dimensions for the caliber.

2. Stability needs to be examined more, if it will be stored for long and especially if stored in quantity and especially if stored sealed.

Actually, unless storage was a big issue, number one is the only one that really concerns me to a large extent. Composition is also very important but it can be easily controlled. Actually particle shape and size likely can be easily controlled too once a little more effort is put into working a process out. As I said before, it would be hard to match high quality commercial powder without a lot of knowledge and work, but something serviceable and safe could be done, especially by those scientifically inclined, in my opinion.

[Edited on 20-3-2016 by Hennig Brand]

Bert - 27-10-2016 at 18:59

I lost track of this thread, a year or more back, some thought it worth stickying and giving a more fitting name.

Jimbo Jones - 28-10-2016 at 01:51

Quote: Originally posted by Bert

In at least one place, the manufacture of improvised powder IS regularly done: Khyber pass!

http://www.rimfirecentral.com/forums/showthread.php?p=518568...

Found this posted by a Pakistani of another forum I'm a member of, with pictures of re-manufactured 7.62X39 rounds using spent cases with home made bullet, primer and POWDER. They are NOT careful reloaders nor accomplished powder makers...

[Edited on 1-11-2015 by Bert]

Looks like crashed Cordite or similar propellant of that type. I highly doubt that someone will invest so much effort to produce it from the basic ingredients.

Hennig Brand - 18-2-2017 at 07:06

I picked up a nice Italian stainless steel pasta maker at a thrift store for about $20. I only fully appreciated how well it would work for making nearly uniform flake propellant once I had it in my hands and examined it. The one I got either didn't have or was missing the spaghetti attachment, but it does have an attachment which can make two different, appropriately sized strips (different widths) and the set of rollers with adjustable spacing of course. Maybe I will crank out some propellant with uniform particle size in the near future (pun intended).

PHILOU Zrealone - 18-2-2017 at 12:59

Quote: Originally posted by Hennig Brand

I picked up a nice Italian stainless steel pasta maker at a thrift store for about $20. I only fully appreciated how well it would work for making nearly uniform flake propellant once I had it in my hands and examined it. The one I got either didn't have or was missing the spaghetti attachment, but it does have an attachment which can make two different, appropriately sized strips (different widths) and the set of rollers with adjustable spacing of course. Maybe I will crank out some propellant with uniform particle size in the near future (pun intended).

Nice idea and inspiration...
I also have one, but never thought to use it for that purpose...so thank you.

Hennig Brand - 19-2-2017 at 02:41

Very welcome. The pasta maker idea was mentioned by Bert and one or two others IIRC earlier in this thread, but I was more focused on other aspects of manufacture at the time and was still developing an understanding of the significance of particle size and shape.

PHILOU Zrealone - 19-2-2017 at 05:45

It has to be devoted to that process ...
otherwise it must be cleaned thoroughtly unless we want cardio-pastas

(nitric esters you know...)

Hennig Brand - 26-7-2017 at 01:42

A little lowering of my blood pressure is sometimes welcome

Ok, I was thinking about safe testing of homemade propellants. Obviously the low tech methods of starting with a small caliber overly build single shot rifle with a strong mechanism such as a tough .22 cal. is a good first move, as well as starting with a light propellant load and gradually and cautiously increasing while looking for signs of excessive pressure (there are normally at least a couple). However, it looks as though modern strain gauges and computers and readily available, or easily made software, would allow us to actually measure chamber/barrel pressure and graph the pressure curve for the firing event.

First article found while googling attached.

Attachment: Instrumenting your rifle.pdf (804kB)
This file has been downloaded 1157 times

[Edited on 26-7-2017 by Hennig Brand]

Fulmen - 26-7-2017 at 05:07

I'm very fond of my old Pressure Trace unit, in fact I find it hard to develop loads without it. Definitely one of the better routes to go.

The simpler one is a standard rifle and a long rope. Measuring either pressure ring or case head expansion won't give as much info as the PT but it should provide usable data.

You should also check out QuickLoad, it's a very useful load simulator that can help you characterize your powders.

BTW, flake powder isn't the worst geometry to work with. Depending on the dimensions it should be fairly neutral burning, and if you sandwich a slow composition between two layers of a faster one you should be able to achieve progressive performance.

[Edited on 26-7-17 by Fulmen]

Nitrosio - 24-4-2020 at 21:17

http://pyrobin.com/files/Nitrocellulose%20Industry.pdf
http://pyrobin.com/files/Nitrocellulose%20Industry2.pdf

B(a)P - 24-4-2020 at 23:14

Quote: Originally posted by Nitrosio

http://pyrobin.com/files/Nitrocellulose%20Industry.pdf
http://pyrobin.com/files/Nitrocellulose%20Industry2.pdf

Brilliant, thanks for sharing!

Nitrosio - 25-6-2021 at 03:02

Attachment: Normgas.pdf (16kB)
This file has been downloaded 511 times

[Edited on 25-6-2021 by Nitrosio]

Nitrosio - 25-6-2021 at 05:13

Attachment: Polymere Sprengstoffe2.pdf (14kB)
This file has been downloaded 470 times

Nitrosio - 25-6-2021 at 14:48

Sorry: [C3H2(O-NO2)2] 162.06g OB:-9.87% N:17.29% 692l/kg

Korrektur

Nitrosio - 28-6-2021 at 01:29

Attachment: Polymere Sprengstoffe2.pdf (14kB)
This file has been downloaded 452 times

specialactivitieSK - 26-8-2021 at 01:07

How much solvent should contain Smokeless Powder mass by pressing to cordite or shotgun pellets.

And whats better as solvent, acetone or mix ether with ethanol ? Thx.

Alkoholvergiftung - 26-8-2021 at 21:58

60-70% the wight of the guncutton are solvent. But bevore you need 30% of wight alkohol to prefent clumping. you can use aceton or an mix of 30/70% ethanol,ethylacetat. source : "Das rauchlose Pulver". For mono Propelant.
The mix was knead together in an machine used for dough making at last one hour.

"for the preperation of Cordit are used 65 parts dry guncutton in form of pressed cylinders 11,2cm high and 7,5 wide they are superficial mixed with 30 parts nitroglycerin and than pressed througt an copper sieve. The raw mass goes to an dough making machine that is filled with 2/3 aceton. After the starting the knead process the remaining aceton (73 parts total) is gradually filled in. After 3 1/2 hours knead time 5 parts Vaseline is added and the machine runs another 3 1/2 hours."

[Edited on 27-8-2021 by Alkoholvergiftung]

specialactivitieSK - 27-8-2021 at 10:47

DEGDN lamels powder, first try with acetone.
Acetone is to quickly for drying, bubbles are there, may be vacuum is a solution for acetone or I try slower ethylacetate or ether, ethanol mix.
Must find technique for porous lamel powder.

[Edited on 27-8-2021 by specialactivitieSK]

[Edited on 27-8-2021 by specialactivitieSK]

Alkoholvergiftung - 27-8-2021 at 21:07

Maybe more solvent. The Book stated first 1 to 1 mix guncutton solvent. 60 to 70% are engouh for production (Industrial).

specialactivitieSK - 27-8-2021 at 23:51

So I used much more acetone. Its better but still Not enough.

specialactivitieSK - 28-8-2021 at 01:58

Explosia reloading manual

https://www.google.com/search?q=explosia+reloading+manual&am...

Alkoholvergiftung - 28-8-2021 at 02:57

They used rolling to highend desteny and to squez out the bubbles bevore they made the noodels.May be an way. Have you tested your powder?

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