Black Powder question

Discussion in 'High Power Rocketry (HPR)' started by Joe Rocket 97, Dec 23, 2018.

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  1. Dec 23, 2018 #1

    Joe Rocket 97

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    Ok. I'm looking into Dual Deploy recovery. My first problem is, Real Black powder is hard to come by in my area. It was suggested by a local gun store to use BP replacement. Supposed to have the same effects in muzzle loaders but burns cleaner. Any advice on this subject? I don't want to get hammered with haz mat on something like this if I can help it
     
  2. Dec 23, 2018 #2
  3. Dec 23, 2018 #3

    MClark

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    Go to a different gun shop. Most gun shop employees know little about modern guns and nothing about black powder.
    BP substitute works well in a rifle at high pressure as designed but poorly for rocket applications. It can be made to work but is not a simple replacement.
    I work at a gun shop.

    M
     
  4. Dec 23, 2018 #4

    Andrew_ASC

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    FFFFG is extremely recommended by HPR flyers. Go with the product Steve showed if in doubt. That’s what is in the Aerotech certified motors for hpr motor eject.

    Going off the beaten path by experience I know 0.6-0.7 grams of P substitute in a tight container sealed will deploy a 12” chute 20 ft out of a 29mm MD airframe. And all the ejection charge calculators failed with P sub. We had to work experimentally in 0.1 gram increments test on ground and ate up a bunch of MJG fire-wires. It was a college rocket competition under a deadline with no time to ship so we used what was local and in stock last year. This year we used FFFFG. Just go with FFFFG.
     
    Last edited: Dec 23, 2018
  5. Dec 23, 2018 #5

    solid_fuel

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    I’m pretty sure the above Andrew means FFFFG
     
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  6. Dec 23, 2018 #6

    Zeus-cat

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    I have used Pyrodex (a BP substitute), but I prefer black powder. Substitutes are harder to use as they must be contained to get a proper ejection. Uncontained, or poorly contained, and the substitutes smolder rather than exploding and generating pressure.

    Are you in a club? Ask other members where they get BP and ask if you can buy some.

    If you use a substitute then pack in something rigid like a centrifuge tube and tape it securely.
     
  7. Dec 23, 2018 #7

    Andrew_ASC

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    Sorry bud fixed.
     
  8. Dec 23, 2018 #8

    Zeus-cat

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    FFFG works, but FFFFG is better.
     
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  9. Dec 23, 2018 #9

    Andrew_ASC

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    Zeus we had the same problems you had with tight containment on P sub. We had to use ultra sticky HVAC tape to form containers for comp, not duct tape ,and also even experimented with epoxying 9/32” auto rubber vac hose. It took many tries to get the method down right. Blackpowder is more reliable.
     
  10. Dec 23, 2018 #10

    grouch

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    I never understand when these BP threads pop up. I get your quandary if you fly alone out in some remote field somewhere but flying at a club launch is not a problem at all. It's easy to get at a launch. I keep a 35mm film canister of it and I rarely fly DD. Make friends at your launch, ask around and pick some off someone else or go in on a group buy. No issues at all.
     
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  11. Dec 23, 2018 #11

    seth_cooper

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  12. Dec 23, 2018 #12

    Joe Rocket 97

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    yes I am. they do group buys but not in the near future
    excuse me for asking
     
  13. Dec 23, 2018 #13

    Joe Rocket 97

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  14. Dec 23, 2018 #14

    grouch

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    A sensitive little thing aren't we?
     
  15. Dec 23, 2018 #15

    Joe Rocket 97

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    not really lol
     
  16. Dec 23, 2018 #16

    Zeus-cat

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    Minimum powder order is 4 pounds, so you are looking at a minimum charge of $85
     
  17. Dec 23, 2018 #17

    manixFan

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    I have to disagree that BP substitutes don't work well. I've done testing and have found they can work very well if handled properly. The most important thing is using a charge holder that creates a strong flame front to burn the powder once it is ignited. Powder is designed to be burned in a barrel. If you use a cylinder as a charge holder you allow the flame to be directed into the same area where the unburnt powder has been dispersed and it allows for a more complete combustion. In my testing the biggest difference is that the substitutes burn slower than the BP and require a bit more powder to produce the same results. Triple7 has the added benefit of producing a lot less corrosive residue than BP. In my testing Hodgdon's Triple7 (se7en) FFFG performed almost volume for volume (not weight) for BP. I have used it without issue.

    Ground testing of course will confirm these results for anyone who cares to test it for themselves.


    Tony
     
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  18. Dec 23, 2018 #18

    Andrew_ASC

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    We had good results with P sub 10/10 tests on ground worked once we dialed containers in. It just wasn’t as lax prep as your standard Aerotech motor eject BP charge. That powder P sub needed to be compressed very hard and very tight to preform well. It’ll work but this forum hates it.
     
  19. Dec 23, 2018 #19

    manixFan

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    I also tested Hodgdon Pyrodex P (FFFG equivalent) and while it did work, it was the slowest burning and required a larger volume increase over a standard BP charge than Triple7. There is no reason why either of them could not be used in place of BP with the proper techniques. And both are a lot cleaner than BP with Triple7 being the best in that regard.

    Anyone not doing a good job containing any kind of ejection charge is leaving a lot up to chance. Just because something works well a lot of the time when poorly contained does not mean it's going to work well 100% of the time. Proper containment of anything used to produce a large volume of gas for an ejection event is critical to ensuring reliability.

    It's important to remember that the BP substitutes work by VOLUME not WEIGHT. So a gram of Triple7 is not the same as a gram of BP. I have always used BP scoops (made by LEE) rather than trying to measure my BP or substitute and have never had an issue.


    Tony

    (edited to add additional info)
     
    Last edited: Dec 23, 2018
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  20. Dec 23, 2018 #20

    Rocketjunkie

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  21. Dec 23, 2018 #21

    David Schwantz

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    Got some Triple 7 FFFG to use. I have charge cans made out of.44 mag cases, MJG ematch for ign. What other tips could of suggest for using Triple 7? Thanks.
     
  22. Dec 23, 2018 #22

    Buckeye

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    This is good info. I securely pack my BP in centrifuge vials. I'll try the Triple7 in the same manner. I like the idea of less residue.
     
  23. Dec 23, 2018 #23

    Random Flying Object

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    I too wanted to move away from 4F BP and went to great lengths to make a proper gas generator. I ended up right back where I started after I found a can of 4F, still using the same original can.

    IMG_1861.jpg
    IMG_4712.jpg
     
  24. Dec 23, 2018 #24

    manixFan

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    I have used .45 Long Colt cases (nearly identical in size to the .44 mag) for up to about a one gram equivalent charge, but for bigger charges longer would be better. I use the LEE PRECISION 90100 Powder Measure Kit to measure by volume. So if you want a 1 gram charge you use the 1CC scoop. In my testing I found that Triple7 was not quite as energetic as BP, so I would do some ground testing by starting with the same amount of T7 as BP and then going from there. A lot depends on how much empty volume you have in your payload bay.

    Also load the match at the top of the powder charge rather than at the bottom. That seems to help ensure more complete ignition. Make sure you compress the charge slightly by filling the empty space in the charge holder with some Estes wadding. I then tape over the top of the holder with a couple of strips of tape, followed by a couple of wraps around to hold those strips in place.

    Hopefully you have an area where you can test without attracting unwanted attention. Otherwise you can use a rocket with motor ejection as a backup where the delay will fire past apogee. You can tell from the altimeter data if it was your charge or the motor that separated the rocket. For those tests you can replace your drogue with a larger chute in case your main charge is undersized and it does not deploy.

    Good luck,


    Tony
     
  25. Dec 23, 2018 #25

    ksaves2

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    Yes, that is a reasonable supplier. For sport fliers 5lbs will last the life of your hobby unless you advance to really large projects. Kurt
     
  26. Dec 23, 2018 #26

    David Schwantz

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    Thanks Tony.
     
  27. Dec 24, 2018 #27

    Nate G

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    new to the forum but a reloader for decades. apologies if this is addressed elsewhere but why not use cleaner burning fast smokeless powders like WST, W231, red dot?
    thanks
     
  28. Dec 24, 2018 #28

    David Schwantz

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    Hi Nate, this is my first DD also. I tried Hodgdon triple 7 FFFG for the first time this morning. No smoke, seemed to have plenty of expansion. Got e match kit from MJG last night, made them and tried them out today. I am at the very least going to continue with that powder for more ground testing. Right now I am taking an idea from back when I was in the "war between the states" and am rolling some paper tubes to load powder and e match into, just like reload for muzzle loading. That way it is just a quick "reload" into my charge cans.
     
  29. Dec 24, 2018 #29

    Nate G

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    sounds like a good idea for containment. I used something similar many years ago for a mini cannon for demos. custom rolled essentially posits could be made to fit in your favorite container.
    My background in chemistry "suggests" that, while BP is a true explosive; smokeless modern powders are "fast burning solids". Amount of containment determines burn rate and they are less dangerous than newsprint in the open and certainly less dangerous than any flammable liquid. also, much more commonly available. by all means , use what you have. 15 years ago when I last considered mid and hi power rocketry, I remember a discussion on this topic somewhere on the net and maybe some experiments but do not remember where it was. suspect this has been tried, just can't find it yet.
     
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  30. Dec 24, 2018 #30

    Eljay

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    Getting the pressure just right would be tricky - black powder doesn't have the same pressure dependence smokeless does. To see this burn a spoonful of black powder just sitting on something that won't burn and then repeat with smokeless. The black powder will be way more energetic. And then of course if you mess it up smokless is so powerful you're screwed. There's not a lot of margin of error. It's not an impossible task but if you really wanted to go there, you would be better off with black powder substitute like 777 that's designed to burn more like real black, but burns a lot cleaner. And even then all of a sudden people are talking about containment and pressure because it's close but it's not the real deal.
     

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