Author Options:

Black Powder for use in fireworks Answered

I want to get into pyrotechnics as a hobby, and i thought i would start with rocketry. So my questions are: What is the best for a lifting charge for fireworks or a rocket, very very fine particles, or coarse granules? i read somewhere on the internet that granules are best, but all over instructables it says to grind it really well. And also, would adding steel powder/magnesium powder to enhance the spark effects alter the BP? like would magnesium make it more sensitive? Please answer, Thanks.



9 years ago

Fireworks rockets are an interesting thing. For MOST rockets, the idea is to get the maximum thrust, so that you can lift the largest payload to the highest altitude. But not a fireworks rocket. A fireworks rocket is largely about the tail/trail of sparks going up, with payload and maximum altitude somewhat secondary. Also, there are certain standard sizes for rockets (including nozzle and core), and the propellant has to be "tuned" for the size of rocket you are making. The same hot powder used in a "1 oz" rocket will cause a larger rocket to explode (prematurely.) To get the most powerful black powder, you want very fine particles, and you want them ground together quite thoroughly. One approach is to start with such a "fast" BP, and add charcoal (and other impurities) to it to slow it down for larger rockets and brighter tails... Type of charcoal is also very important.

What type of charcoal would you reccomend? Hardwood or softwood? and form there, like willow, pine, oak?

Willow is traditional for the fastest powder, but others are supposed to have characteristic sparks. The "air float dust" from pyro suppliers tend to be something like coconut shells.

In some sense, consistency beats absolute performance. I figure that the reason the homebrew amateur rocketry people have so much success with their AP composite motors is that they're dealing with AP having a fixed particle sizes, and other components with exact compositions (resins, catalysts, etc.) None of this "grind your KNO3 (of suspicious origins and unknown impurities) with your charcoal (ditto, only more so) and sulfur (probably pretty pure) in a rock tumbler for a long time (with unknown efficiency in grinding/etc.)
Being able to make that pretty-good rocket AGAIN and again may be better than being able to make a great rocket once.

I dunno; I've never been too interested in rocket tails. There is a pretty active yahoo group for BP rockets ("R-BP", apparently...)


9 years ago

Very, very, very fine particles, and pack, what ever you plan to use, in tight. :-)

Have a look at the 5c Sugar Rocket.

Regarding additives, make it fly before you make it fancy.

thank-you, i found those links to be very helpful and informative =)