Aerial shells are a very popular category of consumer fireworks on the market. We love to watch them anytime of the year, from the Fourth of July to New Years Eve and at many other festivities on the calendar. Most of us take these powerful devices for granted, appreciating how they look bursting in the sky but not understanding much else about the way they operate. Understanding how aerial shells work will make you a more knowledgeable, conscientious and safer firework enthusiast.
The overall design of an aerial shell features four parts, the container, the stars, the bursting charge and the fuse. The container is the outer vessel which is typically made from paper mache and string shaped into a cylinder. Inside the container, stars made from various pyrotechnic compositions wait, ready to dazzle with effects. The bursting charge usually runs up and down the center and is packed with black powder. The fuse gives a time delay so that the shell burst in the air at exactly the right time. On the bottom of the shell, a small cylinder holds the lifting charge.
Artillery shells are launched from a mortar, which is basically made from a length of HDPE or fiberglass tubing. When the lifting charge is ignited, it lights the fuse which then burns through to the bursting charge creating a fiery environment which star setting off the stars waiting within. The special effects of the stars vary based on the pyrotechnician’s design, but usually they are colorful and burn with bright sparks that fill up the night sky.
In simple artillery shells, the stars are packed in the same compartment and are meant to go off at the same time. Multi-break shells burst in two, three or more phases. The effects and stars are more diverse in these fireworks and are kept separate because they are fed by different fuses. Based on the design, the bursting of one set of stars ignites the next section of stars, and so on. The effects vary widely on these aerial effects, from the colors, the sounds and the burst design. Chrysanthemum, palms, peonies, and spiders are just some of the descriptive names of aerial firework designs.