Pyrodex formulation?

[DrJones]

I've searched the forum, but surprisingly, Pyrodex didn't show up. Will you share the formulation, please.

(How Hodgdon got Pyrodex classified as a propellant, same category as smokeless, and totally in a different legal category that BP, was an amazing matter of marketing, salesmanship, and monetizing pyrotechnics. Rare is the gun shop that stocks BP these daze.

Edward

[Carbon796]

I've searched the forum, but surprisingly, Pyrodex didn't show up. Will you share the formulation, please.

 

Edward

That's because pyrodex is useless in real pyrotechnics.

[DrJones]

Thanks Carbon796. Help me here, please. I do not understand the term "real pyrotechnics", nor how Pyrodex is "useless" as a propellant for pyrotechnics. I fully understand that BP is likely the best choice, over Pyrodex, for various reasons. On the other hand, Pyrodex is much more widely available in various granulations than is Goex or other BP. Not everyone is ready, willing, or able to make BP, or buy it. I find that Pyrodex indeed provides excellent lift for 3" mortar shells. Maybe not the Best Lift selection, by any means, yet it seems to me that if Pyrodex indeed provides adequate lift for a pyrotechnic device, it's not by any means "useless."

 

In what ways does Pyrodex qualify as "useless in real pyrotechnics"? What are "unreal pyrotechnics"? I can certainly understand the position of "I would NEVER use Pyrodex in any pyrotechnnics," or "I prefer another propellant," but have a hard time understanding "useless" for "real pyrotechnics."

Thanks in advance.

[SharkWhisperer]

Thanks Carbon796. Help me here, please. I do not understand the term "real pyrotechnics", nor how Pyrodex is "useless" as a propellant for pyrotechnics. I fully understand that BP is likely the best choice, over Pyrodex, for various reasons. On the other hand, Pyrodex is much more widely available in various granulations than is Goex or other BP. Not everyone is ready, willing, or able to make BP, or buy it. I find that Pyrodex indeed provides excellent lift for 3" mortar shells. Maybe not the Best Lift selection, by any means, yet it seems to me that if Pyrodex indeed provides adequate lift for a pyrotechnic device, it's not by any means "useless."

 

In what ways does Pyrodex qualify as "useless in real pyrotechnics"? What are "unreal pyrotechnics"? I can certainly understand the position of "I would NEVER use Pyrodex in any pyrotechnnics," or "I prefer another propellant," but have a hard time understanding "useless" for "real pyrotechnics."

 

Thanks in advance.

Most folks make their own BP. We use BP for much, and you can manufacture it for a few dollars/pound instead of the sky-high price of Goex in quantity. And you can make any formulations and size granules you wish, with varied burn characteristics. Most pyro BP is much hotter/faster than Goex's regulated/opacified burn rate, though slower powders (more charcoal/less oxidizer) are typically used for core-burning BP motors, the hottest you have for end-burners or short-cored motors akin to Estes BP motors. Goex is just not fast enough for those, and the binder makes pressing Goex into propellant grains difficult unless milled back to dust (did I mention expensive?).

 

You can pull the MSDS for Pyrodex (and Triple 7) and get a general idea of what's in it. Pyrodex is basically a potassium perchlorate-enhanced BP, with extra charcoal fuel and some other minor mods that I'd have to locate. Not hard to find the basics in the MSDS. Triple 7, I believe has a benzoate added which is the fuel some whistle propellants. I would imagine it has some of the properties (and potential cautions) of using Benzolift, but have never used Triple 7 for fireworking purposes.

 

Though you have found use for Pyrodex as a lift charge, even that use alone will soon become costly compared to homemade BP that costs only a fraction of BP substitutes or Goex. And be careful with Pyrodex--it's formulated to be a volumetric replacement for more dense Goex/BP, not a mass equivalent. Pyrodex is less dense (i.e., more energy/gram), so swapping it out gram-for-gram can get problematic, particularly with applications that use a lot of powder.

[Carbon796]

Pyrodex is pressure dependent to be effective/efficient. Most pyrotechnic devices will not provide a suitable working environment for it to be useful,reliable, or safe. Not enough pressure its week, too much pressure and your destroying equipment, and putting people at risk.

 

BP is much more linear.

[Mumbles]

Honestly, I'm surprised you're getting good lifting with Pyrodex, especially in a 3" shell. The general consensus has always been that firework shells don't provide anywhere near the chamber pressures to get Pyrodex to burn fast enough for decent lifts.

 

There are various formulations of Pyrodex. In general, I've seen two varieties. One is a smokeless base with some pyrotechnic components similar to the normal pyrodex mix. The more common one I've seen is a modified BP. It generally contains a mix of potassium nitrate and potassium perchlorate as the oxidizer. The fuel is generally a mix of charcoal and a benzoate salt plus some sort of binder. It's basically a blend of whistle mix and sulfurless BP. There are several formulations, so it's hard to give a typical composition.

[SharkWhisperer]

Honestly, I'm surprised you're getting good lifting with Pyrodex, especially in a 3" shell. The general consensus has always been that firework shells don't provide anywhere near the chamber pressures to get Pyrodex to burn fast enough for decent lifts.

 

There are various formulations of Pyrodex. In general, I've seen two varieties. One is a smokeless base with some pyrotechnic components similar to the normal pyrodex mix. The more common one I've seen is a modified BP. It generally contains a mix of potassium nitrate and potassium perchlorate as the oxidizer. The fuel is generally a mix of charcoal and a benzoate salt plus some sort of binder. It's basically a blend of whistle mix and sulfurless BP. There are several formulations, so it's hard to give a typical composition.

The Triple 7 MSDS is here https://hodgdon.com/wp-content/uploads/2017/07/triple-seven-sds-sheet-2017.pdf , and they're a little more open about their formulation than the ranges provided by Pyrodex. 10% sodium benzoate and 30% perc to spice things up. Pyrodex MSDS doesn't list benzoates (but vague memory recalls seeing it mentioned in the patent application), but there's the complete "escaped" formulation posted all over, and it's primarily perched up BP. https://www.muzzle-loaders.com/media/wysiwyg/product-manuals/Blackhorn-209/Hodgdon-Pyrodex-SDS-Sheet.pdf And Dan P., who originally patented Pyrodex, got blown to smithereens when the first Pyrodex factory blew up in '77, so the formulation might have changed. I read a forensic analysis suggesting that benzoate in Pyrodex was replaced with sodium dinitrobenzoate sulfonate. Incidentally, Pyrodex was marketed as a mining explosive well before it became popularized as a muzzleloading propellant. But it fell out of popularity before long when miners started having fatal accidents with it (26% misfire rate for blowing holes in rock using bags of Pyrodex) https://www.fmshrc.gov/decisions/alj/y94-76rm.pdf . Both T7 and Pyrodex are made by Hodgdons now.

 

Although both BP substitutes come in pellets and in granules, the different sizes/formats of each probably contain very similar (if not identical) chemical compositions. MSDSs don't need to include % values of listed components, or all components not considered health/fire/environmental hazards, but many include a wide range of %s, particularly if protecting trade secrets or if variation occurs between products; if, however, they opt to state a single % value, it needs to be reasonably accurate.

 

Both are exempt from BP explosive transport/storage regulations because they have a higher ignition temperature and are less impact sensitive than BP. Actually, if you've ever used Pyrodex pellets, you'll notice that the backside has an "initiation accellerant" that is not Pyrodex, but a darker material that's likely pure BP (in small enough amounts to be exempt from BP regs, like Estes BP motors). That's Hodgdon's version of pellet "priming". Never used Triple 7, so can't really comment on their pellets, but it supposedly burns hotter than BP

 

From OSHA Guidance Brief on MSDSs, https://www.osha.gov/sites/default/files/publications/OSHA3514.pdf :

The concentration (exact percentages) of each ingredient must be specified except concentration ranges may be used in the following situations:

° A trade secret claim is made,

° There is batch-to-batch variation, or

° The SDS is used for a group of substantially similar mixtures.

[SeaMonkey]

Here a some links to some informative articles:

 

Hodgdon: The Inside Story

 

Muzzleloading Babylon, A Very Basic History of Propellant

 

 

Black Powder Substitutes - I

[DrJones]

In 1950, Hodgdon sold bags of war surplus double-base smokeless made for 16-inch naval guns. The grains were about an inch long and thick as my thumb, with seven tiny perforations longitudinal. The shipped to me--a minor--via post, cost was a couple dollars per pound, via American Rifleman ads. Nifty, those grains were. Light and toss, or use the sling-shot.

[SeaMonkey]

Looking back to how much freedom we enjoyed in the 50s is almost like looking at another World.

 

How on Earth did we ever "evolve" to our current state of almost no freedom and the prospect of a tyrannical New Normal?

 

The Land of the Free and Home of the Brave has disappeared.

[Crazy Swede]

I just stumbled over the original Pyrodex formula (in the new book/encyclopedia by Ernst-Christian Koch: "High Explosives Propellants Pyrotechnics") so here it is:

 

45 potassium nitrate

9 charcoal

6 sulfur

19 potassium perchlorate

11 sodium benzoate

6 dicyandiamide

4 dextrin

 

1 additional percent of water is mentioned but I do not know if that was added before mixing or if that is the normal content of moisture ?