Starmines
Starmines 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. I've heard of several different ways to make starmines, and the method described here is just the way I do it. Other methods may be better (this page needs updating), but it works well, especially for smaller to intermediate sizes (say up to 5 cm diameter). The starmine described here consists of a thickwalled paper tube that is tightly sealed by a wooden or clay endplug on one side. The other side is only sealed by a paper plug. In the mine, a lift charge and some stars are placed. The entire device is glued to a wooden base. When the mine is fired, the paper plug will give way, the stars are shot upwards and will reach 10...20 meters height. Then they rain down, and burn out before they reach the ground. The effect is spectaculair, especially with the somewhat larger ones.For a first starmine, 3 to 4 cm inner diameter is a nice size to start with. Smaller is much less spectaculair, and larger is more dangerous. Also: in general it is better to start out small.
materials
Casing: A 17 to 20 cm long paper tube with an inside diameter of 3 to 4 cm, and wall thickness of 5 mm or more.
End plugs Toiletpaper or tissuepaper is used for one end plug. The other is either made from wood, in which case you need a wooden endplug of 1 to 1.5 cm length that fits the dowel, or clay. If clay is used, Bentonite clay works well. I use ground up kitty litter myself. Paper plugs will also work.
Fuse: Visco fuse works fine. A long delay between ignition and effect is preffered. I personally prefer to have a 20 second delay. Quite long, but it allows you to not only reach a safe distance but starmines also look much better from a distance.
Lift charge: Black Powder works well. You may also use Pyrodex, But you have to use MUCH more to get the lift needed.
Stars: Some stars are needed ofcourse. Use between 30 and 50 stars of 1 to 1.5 cm diameter.
The 'open' end
You want the starmine to remain intact (withstand the pressure from the lift charge) long enough to build up sufficient pressure to fire the stars high up in sky. On the other hand, you want to be sure that the stars are actually fired. Not crushed or burst through the sides of the mine. Therefore, the 'open' end should not be actually open, but resist the lift charge for a while, while it should be the weakest part of the device so that you are sure it will burst there. Think of it as a shell with an intented unsymetrical break.
Take the 5 cm piece of roundwood. Place this piece of wood upright on a hard surface, and slide the tube over it. Then stuff several wads of toiletpaper in the one end of the tube. Place a dowel in the tube and use a hammer to compact the paper tightly in the tube. Then take the dowel and the piece of roundwood out. The paper will form a surprisingly strong plug in the tube, although less strong than the walls of the tube. It's thickness should be about 1 cm. After a few attemps you will know how much paper to use to form a plug of this thickness. To get consistent results, use the same amount of paper every time. If you ever decide to make a larger diameter mine or the stars do not reach an appropiate altitude, use more tissuepaper or ram it more tightly (try the latter first).
The fuse
It is better to add the fuse before the lift charge and stars. The fuse is inserted through a hole in the side. So first drill a hole with a small diameter drill, just 2 cm of the bottom end of the mine (so that it wil be slightly above the end plug). I use a 1 mm drill and insert a 20 cm piece of visco fuse. More for bigger mines. The 1/8" visco sold at www.pyrocreations.com will work well. I bend the fuse inside the mine and secure it with a drop of hot melt glue or a piece of paper tape. twist it around the tube gently, and tape it lightly so that it won't be in your way (you could damage it) during the next steps. Like mentioned, I use 20 cm of visco. That allows about 17 seconds to get away. You need that much time not only to be at a safe distance in case something should go wrong but also because a starmine looks so much better when viewed from a distance.
The contents
The starmine contains some stars and a lifting charge.You can use just about any type of stars, including cut stars and rounds stars. Use stars of 1 to 1.5 cm size, and fill about 3/4 of the starmine 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. Even black powder of inferior quality (black powder made without a ball mill, also known as polverone) can be used. If you use good quality black powder a few grams (2 to 3 grams) will do. Otherwise, fill the starmine with blackpowder completely. That is, leave 2 cm of space for the end plug but cover the stars with black powder. Tap the case to settle the powder.
The endplug and base
Finally, glue the endplug in the tube. I use hot melt glue, which seems to cause no troubles. Other glues may work fine too. Make sure the endplug fits the tube tightly. If required, tape a few layers of tape (without wrinkling) around the plug to increase its diameter somewhat. Then glue the entire starmine on a robust wooden base. Always do that, since it will prevent the starmine from falling over when it is placed on an uneven surface. It is a good idea to bury the starmine partially, leaving the fusehole just above the surface.
Firing your starmine
Pick an open piece of terrain for firing the mine. An open field without cattle is perfect. You cannot damage things, and the effect can be fully appreciated in the open. The main dangers of the starmine are the fire hazard of the burning stars and the mine falling over, launching the stars horizontally (which can be avoided by using a proper base). Take enough distance, otherwise you risk getting burning stars or glowing ashes all over you.
