Pyrotechnic Projects: Star Mines
Star mines are devices that fire a cloud of stars up into the sky. The effect is short, but spectacular and they are very commonly used in professional displays. In the mine, a lift charge and some stars are placed, and when fired, the stars are shot upwards and will reach 30 to 60 feet height and rain down, and burn out before they reach the ground. The effect is spectacular, especially with the somewhat larger ones. Smaller is much less spectacular, and larger is more dangerous. In general it is better to start out small.Materials:
Casing: Heavy walled paper tube.
End plugs: Toilet paper or tissue paper is used for one end plug. The other is either made from wood, clay, epoxy, hot glue, plaster etc.....
Fuse: Visco fuse.
Lift charge: Black powder works well.
Stars: Some stars are needed of course. Use between 30 and 50 stars of 3/8" to 5/8" diameter.You want the star mine to withstand the pressure from the lift charge and build up sufficient pressure to fire the stars high up in sky, therefore the 'open' end should not be actually open, but closed as to slightly resist the lift charge.Take a 2" length of dowel that is the same diameter as your tube and slide the tube over it, stuff several wads of toilet paper in the end of the tube and use a dowel and a hammer to compact the paper tightly in the tube, continue until the paper plug is about 3/8" thick and then take the dowels out. The fuseIt is better to add the fuse before the lift charge and stars. The fuse is inserted through a 1/8 hole in the side about 7/8" from the bottom and insert a long piece of Visco fuse, twist it around the tube gently, and tape it lightly so that it won't be in your way. The contentsThe star mine contains some stars and a lifting charge. You can use just about any type of stars, fill about 3/4 of the star mine with them. Add the stars in small portions taping the case after each addition to settle the stars. Black powder is used for the lift charge. If you use good quality black powder a few grams (2 to 3 grams) will do. If you use inferior quality black powder (made without a ball mill) fill the star mine with black powder completely except for 7/8" of space for the end plug. Tap the case to settle the powder.The final end plug and baseFinally, glue a wooden end plug in the tube with Elmer's or hot melt glue. Glue the entire star mine on a sturdy wooden base.
Firing your Star Mine:
Pick an open area with no fire hazards. The main dangers a starmine are fire, the mine falling over or launching the stars horizontally instead of vertically. You should be far away from starmines, not just for safety but because they look better from a distance. It is also a good idea to bury the starmine partially.