Fireworks: History, Materials, and Manufacturing Process

Background

A firework is a device that harnesses combustion or explosion to produce striking visual and auditory effects. Modern pyrotechnics extends beyond traditional fireworks to include flares, matches, and even solid‑fuel rocket boosters used in spaceflight.

The earliest precursors date back to 2,000 years ago in China, where paper or bamboo tubes filled with finely ground charcoal and sulfur produced flashes of fire and smoke—no explosion yet. It was the addition of saltpeter that gave birth to black powder, the world’s first chemical explosive, roughly a millennium later. Scholars attribute the invention of black powder to Chinese chemists, though some suggest an Arab origin.

In China black powder served multiple roles: fireworks, signal devices, bombs, and rockets. By the 14th century it reached Europe, where it powered both celebratory fireworks and firearms. The 17th century saw its use in mining and road construction. Black powder remained the primary gunpowder until nitrocellulose replaced it in the late 19th century, and industrially by dynamite in the early 20th century—yet it is still indispensable in fireworks today.

Chinese fireworks evolved from simple firecrackers into the elaborate displays that captivated 16th‑century European explorers. In Europe, military explosives were repurposed for victory celebrations, eventually giving way to the intricate productions of Italian pyrotechnists during the 16th, 17th, and 18th centuries. Today, many of the United States’ largest firework companies trace their roots to Italian‑American families. Italian displays favored ornate wooden stages—often floating on water for safety and reflection—while German spectacles tended to shoot fireworks directly into the sky.

Although the Italian masters’ displays were artistic marvels, the technology of the era limited color and brightness. The 19th century breakthrough came with aluminum and magnesium, boosting luminosity, and with Claude‑Louis Berthollet’s potassium chlorate, which enabled richer hues.

Fireworks arrived in the New World with the earliest settlers and have marked American Independence Day celebrations since the country’s birth. The early 20th century saw larger, more powerful fireworks, leading to over 4,000 deaths between 1900 and 1930. In response, federal and state regulations emerged in the 1930s, classifying explosives into Class A (dangerous substances such as dynamite and TNT), Class B (professional display fireworks), and Class C (small fireworks for private use). Class C fireworks may contain no more than 50 mg of explosive. Some states allow all Class C fireworks, others only "Safe and Sane" fireworks (those that do not leave the ground), and some ban private use entirely. Illegal devices such as cherry bombs, M‑80s, and silver salutes—banned nationwide—continue to cause the majority of modern fireworks injuries.

While private use remains tightly regulated, public displays have become increasingly sophisticated. Computers time launches precisely, allowing choreography with music; lasers add unique visual effects. Today, fireworks are produced and showcased worldwide, especially in Europe, Latin America, the United States, and Japan.

Raw Materials

A modern firework shell consists of a plastic, papier‑mâché, or heavy‑paper outer casing that encloses compartments separated by cardboard. At the base is a black‑powder chamber that propels the shell from an iron, aluminum, plastic, or heavy‑cardboard mortar. A larger chamber holds “stars”—chunks of colorants and oxidizers that emit light when heated. In Western fireworks the stars are mixed with black powder inside a cylindrical compartment; in Asian fireworks the stars surround a central black‑powder core, producing a symmetrical burst. Flash powder chambers replace black powder and stars in certain devices to create a sudden bright flash and loud bang. All compartments are sealed with fuse threads—threads blended with gunpowder grains.

Black powder composition: potassium nitrate (75 %), charcoal (15 %), sulfur (10 %) by weight. Flash powder: potassium chlorate or perchlorate, sulfur, aluminum. Stars: a fuel (charcoal, dextrin, red gum, or metals such as aluminum, magnesium, titanium), a coloring agent (e.g., aluminum, magnesium, titanium for white; carbon or iron for orange; sodium compounds for yellow; copper compounds for blue; strontium carbonate for red; barium nitrate or chlorate for green), and an oxidizer (potassium perchlorate or ammonium perchlorate). Chlorine from the oxidizers reacts with copper, strontium, and barium compounds, forming unstable chlorides that emit the characteristic colors.

The Manufacturing Process

Making the Stars

• 1. Ingredients are sourced from chemical suppliers and stored in sealed barrels. When mixing, powders are scooped, weighed, and sifted twice through brass screens to remove lumps—brass is non‑spark‑generating. The sifted powders are spread on a large paper sheet and blended by hand or in a rotating drum with stationary paddles. Care is taken to avoid friction‑generated heat or trapped powder.
• 2. The blended powder is mixed with water to form a soft dough. Portions are packed into large paper‑lined wooden molds shaped like bread loaves, then tamped with a wooden mallet. The wet dough is far safer to handle than dry powder.
• 3. The loaves (≈35 lb / 16 kg each) are unmolded onto a cardboard‑lined workbench sprinkled with black powder. They are cut in one direction to create slices, then diced into 0.06–2 in (0.16–5 cm) cubes. The black powder coats the wet dice, aiding combustion. The dice are left to dry on paper‑covered screens.

Making the Breaks

• 4. Dried dice become stars. They are transferred to a packing room, where a hollow cardboard tube is inserted into a cylindrical container and stars are poured around it. A large container can hold up to 900 stars (≈4.4 lb / 2 kg). Black powder is poured into the hollow tube, then the tube is removed, filling the interstices between stars and acting as an ignition bridge. The container, now called a “break,” receives a paper cap.
• 5. The break is spiked by wrapping it with heavy string: a large spool is tied to one end, wound around the break, then cut and tied. Some breaks are built from reinforced plastic or heavy cardboard instead of spiking. A time fuse— a short, slow‑burning fuse that detonates after a set interval—is inserted, and the break is wrapped in heavy paper. In the pasting room, the paper is saturated with paste and dried for ~48 h, forming a tight seal.
• 6. Salutes (loud bang devices) replace stars with flash powder, poured into thicker, stronger cardboard containers to build higher pressure before bursting. Salutes are then spiked and pasted like other breaks.

Making the Shells

• 7. Dry breaks are moved to the finishing room and assembled into shells. Asian shells—spherical—contain only one break. Western shells—cylindrical—can stack multiple breaks, allowing multi‑color bursts. Typical multi‑break shells hold 3–4 colored breaks plus a salute; larger shells can hold up to 10 breaks, and a record shell held 22 breaks. The shell is constructed by stacking components, attaching a starting fuse (long, fast‑burning fuse to ignite the launch powder), wrapping in heavy paper, and tying with string. Completed fireworks are labeled and stored until use.

Making Small Fireworks

• 8. Small fireworks for private use follow a similar process but are simpler and contain less explosive material. Examples include firecrackers (paper tubes with a small charge), fountains (paper cones releasing colored sparks), Roman candles (long tubes with multiple small stars that fire sequentially), smoke balls (single chemical wrapped in paper or foil), snakes (ammonium dichromate that slowly burns), and sparklers (metal wire coated in a slurry of fuel, oxidizer, coloring agent, and aluminum granules).

Launching the Fireworks

• 9. Professional displays are typically launched by the manufacturers themselves. Set pieces—ground‑based displays forming pictures or words with flares called lances—are designed on graph paper and constructed by carpenters using thin wooden slats shaped to the design. When music accompanies the show, timing is planned to match the tempo.
• 10. Hours—or days—before the event, crews arrive with fire extinguishers, first‑aid kits, and mortars positioned in prepared holes or steel drums filled with sand. Smaller mortars rest on wooden racks. The appropriate shell is loaded, frames for set pieces are assembled, lances attached, and fuses secured. The show begins when lances and mortars are lit via long hand‑held flares or electrical wires linked to a central switchboard. After the display, crews safely dispose of any unexploded duds.

Quality Control

Safety is the paramount quality‑control criterion. Factories are secured with chain‑link fences, barbed wire, locked gates, steel doors, and tamper‑proof locks. Inside, numerous precautions mitigate risk.

Electricity poses the greatest danger; a single spark can ignite a roomful of explosives. All electrical outlets are located outside the building. Workers wear 100 % cotton clothing, ground themselves on a copper plate before entering, and wear elastic straps with wires connected to grounding rods beneath the floor to drain static electricity. If a thunderstorm is forecast, all work stops and personnel evacuate.

Additional safety measures: all work is manual to avoid spark‑producing machines; buildings are heated with hot water rather than hot air in winter; structures are small so exits are within one or two steps; exit doors open wide with a gentle touch; explosive chemicals are never mixed wet; drying processes are carefully monitored to prevent gas release.