Black powder

Caution:

Black powder burns extremely hot and could cause severe burns if mistreated safety equipement is advised when working with black powder

BALL MILL

The ball mill is one of the most important pieces of equipment in making fireworks, it is used to grind down chemicals and in making high quality reproducible black powder. A few safety precautions should be observed:

1. Never mill any formula except black powder or variations of black powder, individual chemicals are ok, but grinding potassium chlorate in a mill which had contained sulfur, sulfides, ammonium salts, copper salts even after it has been washed, it takes only trace amounts of these chemicals to cause an explosive reaction. Using a different set of pellets is also necessary.

2. Never use anything but lead or brass pellet as mill media because it has been proven to not spark, using steel, glass or ceramic balls may cause an ignition from sparks.

3. Be aware of static, before unloading your mill make certain that there is no static charge that has built up on the barrel, be certain to touch a grounded plate before opening the ball mill, black powder is relatively insensitive but when it is finely powdered it can form a cloud of dust, which can be set off easily, waiting 1/2 hour before opening the drum will help to eliminate that problem.

Making it

Things you will need

Ball mill with milling jar: Loretone rock tumblers work fine for a ball mill, but one that is constructed yourself can be made to mill powder quicker and more efficiently, ex. My loretone tumbler would mill a batch of black powder in 19 hours and my home made mill will do it in five. instructions are available on Dan's tool page(the link is on the left)The design is not set in stone, I built mine with a smaller motor and whatever surplus parts I had kicking around the shop.

mill media: The best media would be 1/2" X 1/2" brass pellets, I use both brass and hardened lead pellets with similar results, the proper amount will fill your milling jar half full

75% Potassium nitrate, 10% Sulfur and 15% Charcoal

Accurate triple beam balance or electronic scale: should be accurate within 0.1 gram

MEASURES USED WILL BE FOR A 4" MILLING JAR(change them accordingly for larger jars)

1. Measure out 150g of KNO3, 20g of sulfur and 30g of charcoal
2. Add pellets and chemicals into milling jar
3. Close lid tightly and secure with duct tape if nessessary
4. Place ball mill outside, (an old deep freeze provides good shelter from the elements and helps to contain flames if an ignition happened.
5. Place milling jar on the ballmill rollors, turn on mill and make sure the jar is rotating at around 100 to 110 rpms
6. let it run for 24 hours, shut the mill off and remove the jar.
7. Screen black powder to seperate the mill media from the powder

Sounds simple, right? Maybee not.

The photo at bottom is a 3" ball of solid black powder. I measured out my chemicals as usual(using two jars this time)
The rubber jar is using brass media and the pvc jar is using lead. I let them both mill for 24 hours. Out of the rubber jar I got a finely ground powder and out of the pvc one I got a 3" solid ball of bp(3" hemisphere along side for comparison)

Sonic Boom