How fireworks are made

On New Year's Eve, about 1,000 times more birds are in flight than on other nights, flushed up by fireworks.

stations: 6
things upstream: 64
raw sources: 18
steps from the ground: 10

The short version

Fireworks are built in licensed factories where each step is separated into small buildings. Workers make paper tubes and shells, load them with the colored and sound-making parts of a design, and add fuses. Finished products are dried, packed in strict limits and kept in approved stores. Only trained crews fire the big shells.

Roll the paper tubes

Casings are rolled from paper and cardboard and glued. Their length and thickness set the size of a shell or the number of shots in a cake.

Goes in
Paper Cardboard
Prepare the effect parts

In small, separated rooms, trained workers prepare the pellets that give each firework its colors and effects. Rooms are kept clean, damp and free of sparks, and only a limited number of people are allowed in.
Load the casings

Casings are charged with black powder, made from charcoal, sulfur and an oxidizer, that supplies the lift and the burst, along with the pellets for the effect. A shell designed to burst into a flower is loaded differently from one that cracks loudly.

Goes in
Charcoal Sulfur
Wrap and fit the fuses

Shells are wrapped with strong paper or string, and fuses are attached to start the sequence at the right instant.

Goes in
Paper Sewing thread
Dry the finished pieces

Completed items dry in the sun or in a heated room, away from fire sources, until they are ready for testing.
Test samples and pack

Samples from each batch are fired in a test area, and approved stock is packed in small quantities for safe transport.

Goes in
Cardboard box

End of the lineFireworks

Worth repeating

During the Song dynasty, people made the first firecrackers from tubes of rolled paper filled with gunpowder, after earlier ones used exploding bamboo.
A single firework cake can contain more than 1,000 shots.