Ejection Powder?

[MontanaSoftware]

Hi ... I need to buy some new ejection powder, and I'm wondering ... is Triple 7 really worth the extra money? What about Pyrodex P? Does that work well?

Also, has anyone tried this ... $10 powder?

Your thoughts appreciated.

 

[noffie79]

I've heard that black powder substitutes are not as reliable as the real thing. It has to be packed super tight in order to get the ejection to work, and can be unreliable. If I were you, I'd try to find some FFFFg black powder. I've never tried a substitute, so YMMV.

 

[cbrarick]

I've worked with the Yale team which has to use the pyrodex. Yuck. The only way to get a good charge is to wrap the crap out of it with electrical tape, and TIGHTLY. Do at least 2 ground tests. We use 1.5 times what is called for in BP. Now they "borrow" my bp.... much easier...they just have to launch where I am or make other arrangements.

 

[MontanaSoftware]

Are you using homemade BP? Goex?

 

[Bat-mite]

Most of us use Goex. Whatever you end up using, make sure you ground test it in every rocket. 4g of FFFFg != 4g of Pyrodex.

 

[rharshberger]

Most of us use Goex. Whatever you end up using, make sure you ground test it in every rocket. 4g of FFFFg != 4g of Pyrodex.

We use a real BP of which Goex and Swiss are two brands, the are others. But BP is easier to work with than the substitutes.

 

[neond7]

Buy a couple pounds of 4F and it should last you MANY years - I'm still on my first pound. Its proven to work, although some people seem to like to "tinker" with substitutes with mixed results. For most of my 4" airframes, 1.5g of 4F in the blast caps have been 100% successful.

 

[RocketFeller]

On the subject of BP, does 4F really work that much better than 3F? I can buy 3F locally, but I can't seem to locate 4F anywhere nearby.

 

[Bat-mite]

I only use 4F, but from what I understand, 3F is a bit less refined and thus needs to be packed more tightly. But lots of people use 3F.

 

[Banzai88]

3f will work just as well for deployment charges. It has slightly larger particles than 4f, and needs no specially different handling or prep over 4f.

BP substitutes suck.

 

[Bat-mite]

The key is, whatever you test with, use that exclusively. If you find a way to get good deployments with pyrodex, stick with it. But I would look a bit more exhaustively for real BP before settling for pyrodex.

 

[cerving]

I've only ever used Triple Seven, it works just fine. All you need to do is to fill up any empty space in the charge well with dog barf, and put several pieces of masking tape over the top and it's all good. As far as it not being that energetic, I have a few destroyed Doghouse Rocketry charge well that will dispel that notion.

I've heard that black powder substitutes are not as reliable as the real thing. It has to be packed super tight in order to get the ejection to work, and can be unreliable. If I were you, I'd try to find some FFFFg black powder. I've never tried a substitute, so YMMV.

 

[noffie79]

I've only ever used Triple Seven, it works just fine. All you need to do is to fill up any empty space in the charge well with dog barf, and put several pieces of masking tape over the top and it's all good. As far as it not being that energetic, I have a few destroyed Doghouse Rocketry charge well that will dispel that notion.

That's why I said his mileage may vary. But it seems to me by reading the other comments, more people have had problems with BP substitutes than not. So, I'll be sticking with the reliable 4F.

 

[soopirV]

I've only ever used Triple Seven, it works just fine. All you need to do is to fill up any empty space in the charge well with dog barf, and put several pieces of masking tape over the top and it's all good. As far as it not being that energetic, I have a few destroyed Doghouse Rocketry charge well that will dispel that notion.

I use Triple Seven too- a little bit more expensive than Pyrodex, but have not had any issues. I do wrap the canister (I use microfuge tubes since I can get them so easily at work) with a couple layers of electrical tape following what I read on Pratt Hobbies page- a really awesome article on the subject I think: https://www.pratt-hobbies.com/info_pages/pyrodex/pyrotest.htm

There's another article I found deep on the interwebs that is worth a read- format is a bit hard on the eyes, but it's also got some useful info for BP substitutes:
https://www.alaska.net/~aleckson/rockets/smokless.html

All credit to the original authors.

 

[Igotnothing]

I find it interesting that so many are able to get 4f. It is nearly non-existent here, but Pyrodex P and RS are available. In theory, we should not want the snappy report of 4f nor P because we are not trying to get that rapid of a pressure buildup. 4f and P are designed for muzzleloading pistols - where the bullet time in barrel is short and the bullet needs to accelerate rapidly. 3f, 2f and RS are for rifles and smoothbores where the bullet, while reaching perhaps 3 times the muzzle velocity, has 4 or 5 times as much time in the barrel.

Pistol muzzle velocity 700 fps, in 6 inches of barrel
Rifle muzzle velocity 1400 fps, in 26 inches of barrel
The rifle bullet has perhaps 300% more mass
The rifle and pistol barrel cross sections could be identical - meaning identical strength

The trick to avoiding unburnt powder is to have the system contain the burning and unburnt powder long enough to burn all the powder - just like the shooters do. Atmosphere outside of the containment devise is just one part of the system resisting expansion of the powder. High altitude deployment may have less "containment" of loose powder expanding ahead of the wave of burning powder if the system is insufficiently contained at the beginning of the burn. The gun will still fire in space because the bullet fully contains the powder burn by spending time in the barrel plugging the powder's exit path - while your deployment charge goes "puff" or even "snap!", scatters unburnt powder through the laundry into cool corners of the payload bay, and fails to separate your rocket.

Deeper charge wells (with long dog barf and tape plugs) will extract the potential of whatever powder you put in them by getting more of it to burn.

 

[tim cubbedge]

You can buy it online from several powder dealers and I would think any decent onsite motor vender would have it, at least that's my experience.

By the way, 4F is used mostly in the flash pan.

 

[rharshberger]

You can buy it online from several powder dealers and I would think any decent onsite motor vender would have it, at least that's my experience.

By the way, 4F is used mostly in the flash pan.

As noted, 4Ffffg black powder is generally used as priming powder for flintlock rifles and pistols (iirc is also used as a pistol powder in percussion ignition black powder pistols), 3Fffg is used as the main charges in black powder rifles and pistols.

 

[MontanaSoftware]

Thank you to everyone for your replies. I've decided to make some crimson powder - per Richard Nakka's recipe - to try it out. He says it has the following advantages over black powder:

- lower combustion temperature which minimizes heat damage to the rocket
- higher impetus (i.e. more potent)
- combustion residue is odorless and cleans up readily with warm water

I just bought enough supplies to make 2+ pounds for less than $13.00. If you folks are interested, I can start a new thread detailing my results.

Thanks!

 

[gerbs4me]

I learned a lot about different powders. TRF is so great!

 

[tim cubbedge]

Thank you to everyone for your replies. I've decided to make some crimson powder - per Richard Nakka's recipe - to try it out. He says it has the following advantages over black powder:

- lower combustion temperature which minimizes heat damage to the rocket
- higher impetus (i.e. more potent)
- combustion residue is odorless and cleans up readily with warm water

I just bought enough supplies to make 2+ pounds for less than $13.00. If you folks are interested, I can start a new thread detailing my results.

Thanks!

I read his article. He says he only uses Crimson powder for main deployment but still uses BP for apogee/drogue.

 

[RocketFeller]

Thank you to everyone for your replies. I've decided to make some crimson powder - per Richard Nakka's recipe - to try it out. He says it has the following advantages over black powder:

- lower combustion temperature which minimizes heat damage to the rocket
- higher impetus (i.e. more potent)
- combustion residue is odorless and cleans up readily with warm water

I just bought enough supplies to make 2+ pounds for less than $13.00. If you folks are interested, I can start a new thread detailing my results.

Thanks!

Very interesting! One downside might be that you can only make ten grams at a time.

 

[YodaMcFly]

I find it interesting that so many are able to get 4f. It is nearly non-existent here, but Pyrodex P and RS are available. In theory, we should not want the snappy report of 4f nor P because we are not trying to get that rapid of a pressure buildup. 4f and P are designed for muzzleloading pistols - where the bullet time in barrel is short and the bullet needs to accelerate rapidly. 3f, 2f and RS are for rifles and smoothbores where the bullet, while reaching perhaps 3 times the muzzle velocity, has 4 or 5 times as much time in the barrel.

Not entirely correct. Pyro P is roughly equivalent to 3F, and, yes, it's mostly intended for use in pistols. 4F is finer, and (in firearms) basically only used for priming flintlock pans. If you loaded a pistol with the same volume of 4F that you use 3F/Pyro P, you'll have an *extremely* hot load, that might be bad for the gun.

Sadly, there is *much* misinformation and misunderstanding about the Holy Black and its substitutes out there on the intertubes.

 

[MontanaSoftware]

One downside might be that you can only make ten grams at a time.

Yes ... I believe Nakka probably limited the size of the recipe as an important safety consideration. In the first version of his instructions, he recommended drying it in an oven at low temps. Later, he changed that to drying in a homemade desiccator (rock salt in a tupperware container), which makes good sense. His website has become very popular, which might attract some irresponsible people. I completely agree with his commitment to safety.

When I said "2+ pounds", I didn't mean to imply that I would make a higher volume per batch. Due to shipping, it only cost a few dollars extra to buy supplies in much larger quantities, so I basically have enough materials to last a long time.

 

[Graduator]

I had looked at the Nakka website many times and had considered trying to make crimson powder myself. I came to the conclusion that the risk was more than I wanted. You could also make black powder if you really wanted too, but that seemed even more dangerous. I have several sources for Goex 4F now, but that was not always true. But heck, every reload comes with powder for one charge, and I know that Aerotech/Valuerockets sold those vials at one time. I bought a pound of substitute way back before I found 4F, but hardly ever used it. It took me a long time to use up my first can of Goex. I felt like it was a right of passage when I drained that can, and I kept it too! I think I paid around $16 for my first one, and it's only $20 today. I think it's the cheapest thing in my rocketry budget.

 

[warnerr]

a lot of trouble in making that powder: each batch can be a bit different in its characteristics- in making traditional BP that is what the pros are good at. If BP is not available at all locally consider mail order- just swallow the price of hazmat as the cost of years worth of consistent results. The substitutes are not explosive like BP and unless contained correctly, will fail.

 

[MontanaSoftware]

Thank you to everyone for your advice. I've read it over carefully and appreciate your willingness to help.

One thing I forgot to mention: This is for little C, D, and E sugar motors that I fly in small and medium rockets. It's just the tiny bit of ejection powder that you pour into the top of the motor. No dual deployments, ejection capsules, or anything else. A very small amount of powder in a small rocket.

I'll make a little batch of crimson powder, test it in a ground stand, and let you know my results.

 

[bobkrech]

Thank you to everyone for your replies. I've decided to make some crimson powder - per Richard Nakka's recipe - to try it out. He says it has the following advantages over black powder:

- lower combustion temperature which minimizes heat damage to the rocket
- higher impetus (i.e. more potent)
- combustion residue is odorless and cleans up readily with warm water

I just bought enough supplies to make 2+ pounds for less than $13.00. If you folks are interested, I can start a new thread detailing my results.

Thanks!

MontanaSoftware

4FG Black powder is universally used for ejection charges in hobby rocket motors because it works better than any other low explosive material. Pyrodex(R) and other black powder materials have been used by some hobbyists in place of BP but significantly more attention to detail is required as the burn rate of black powder substitutes is significantly slower than BP at atmospheric pressure. The behavior of black powder substitutes in firearms at 10+Kpsi chamber pressures does not apply to atmospheric combustion, and it is well documented the action of black powder substitutes is unreliable unless the charge is confined in a container that allows for complete particle ignition before pressure release.

Crimson powder is one of many ascorbic acid based black powder substitutes. Ascorbic acid based black power substitutes do not age well due to the degradation of the ascorbic acid. https://www.chuckhawks.com/blackpowder_roundup_2010.htm https://gunsmagazine.com/chosing-a-black-powder/ and have not been commercially successful due to unreliable results. ATK Black Dot was an ascorbic acid based black powder substitute that is no longer available manufactured for ATK by a NH company that blew up. https://weaponsman.com/?p=10896

Making BP or any BP substitute is inherently dangerous and requires a BATFE explosives permit. Grinding dried low explosive powders is exceptionally dangerous and has resulted in severe and sometimes fatal burns. For these two reasons detailed discussions on amateur manufacturing of ejection charge materials such as black powder and black powder substitutes such as crimson powder are not permitted in the TRF public forums by forum policy. If you decide to go ahead and make crimson powder, don't bother to post the results here as such threads will be removed.

Bob

 

[Onebadhawk]

I don't understand why all of this over 4F BP... again and again...
Someone here in this thread just said that gram for gram 4F is equivalent to pyrodex...
That is totally untrue / false..
Everyone in the pacific north west seem to have trouble getting 4F BP locally..
It is very easy to buy online...
You are adding way to many variables to a flight to use anything but 4F BP...
Also, some of you are flying large heavy projects...
That is definitely not where you want to start introducing variables and experimenting with what will separate the rocket at apogee...
There is a great risk of a failed flight and a lot of work and expense down the drain or worse in the name of "I couldn't get the 4F BP"...

Here--
https://www.grafs.com/retail/catalog/product/productId/5450
Or here--
https://www.buffaloarms.com/Content.aspx?PAGE=Black Powder
or here you can buy 5 lbs and split it up if some of you are local to each other--
https://mainepowderhouse.com/goex-black-powder-4f-25lbs/

This is a fairly common topic here...
Great risk,,, zero return ( as the best you can hope for is the same successful flight as with 4F BP ),,, and no reason for this...

Buy the 4F Black Powder and enjoy jiving out the rest of your flight...
For sure,,,
if there was an aspect of rocketry that I felt was a risk of getting me really badly burned or worse,,,
I wouldn't be into rocketry...
And I am not an overly cautious person.....

Teddy

 

[Sooner Boomer]

I don't understand why all of this over 4F BP... again and again...
Someone here in this thread just said that gram for gram 4F is equivalent to pyrodex...
That is totally untrue / false..

No. NOT gram-for-gram. It is a *volumetric* equivalent. That means scoop-for-scoop (or whatever measure).

 

[Onebadhawk]

No. NOT gram-for-gram. It is a *volumetric* equivalent. That means scoop-for-scoop (or whatever measure).

This is what was posted above by someone,, earlier in this thread--

4g of FFFFg != 4g of Pyrodex.

Teddy