Independence Day is nigh, and that means flags, feasts and…fireworks. Because we’re patriotic nerds, we couldn’t resist taking a timeout to talk about the chemistry and logistics behind the bang. We caught up with Hamilton’s own Cell Tech Ray Casey, who has a side gig running fireworks shows for a company called Legendary Entertainment, about what goes into the pomp and circumstance every 4th of July.
But before we talk to Ray, first a brief lesson in fireworks 101.
Anatomy of a firework
- Black powder: The propellant, made from potassium nitrate, sulfur and charcoal
- Mortar: The outer cylinder chamber, usually made of plastic or metal
- Stars: The pyrotechnic compounds that explode and create colors and effects like showers or sparks
- Shell: A hollow sphere made of pasted paper and string that gets packed with stars
- Bursting charge: Located inside the middle of the shell to ignite the firework
- Fuse: Allows a time delay for the explosion
What determines the color of a firework?
The color is determined by burning the metal salts. When heated, the metal atoms in the salts are excited to a higher energy state. When they cool back down, they emit color. Different salts make different colored flames. Blue fire is particularly hard to create, because copper salt needs a very precise temperature to be excited to the energy state that emits blue light.
How are patterns created?
The stars are thrown out into a pattern when the firework explodes. The pattern in which stars are packed into the shell determines their pattern in the sky. For example, if they are packed into a happy face, they maintain that shape in the sky. Check out this slideshow on Popular Mechanics that shows how some of the most complex designs get created.
Now that we know a little more about what we’re dealing with, let’s talk to our fireworks aficionado, Ray Casey.
Ray, what types of shows do you put on?
Ray: I do everything, from city events to weddings. I even do a Homecoming show for a local high school every year.
Hamilton: What’s the best part about your job?
Ray: Hearing the crowd roar at the end, knowing that you’ve put on a good show.
Hamilton: What’s the most challenging show you’ve put on?
Ray: We did a racetrack show in Pennsylvania once that had to be coordinated with computer programming in two different areas of the track. We had to time the shells and the music just right.
Hamilton: What are your favorite types of fireworks?
Ray: I like the salutes—those are the big bangs that usually wind up at the end of the show. I also like the kamuros. They’re the ones with the long flowing tails that last longer.
Hamilton: What do you want people to know about fireworks?
Ray: There’s a lot of safety involved. We still hand-light a lot of our shows. We wear helmets, gloves and a racing fire suit. It’s not as stringent as the one drivers wear, but it’s still fireproof material.
Hamilton: What goes into a typical show?
Ray: I’m there anywhere from 8 the morning until 2am. The first thing we do is let the fire department know we’re on site. It takes a while to unload all our equipment. Every shell has its own tube. There’s anywhere from 500 to 2,000 shells or more in a single show. You have to get all your tubes in position and angled right. If it’s an electronic show, you have to put an igniter on every shell. Once everything is set up, we check our computer system for bugs. Then we suit up and have a safety meeting with our crew. After showtime, we have a minimum 15-minute cool down before we start the clean-up to make sure there aren’t any more shells that still might go off.
What’s your advice for people doing DIY fireworks this holiday?
Follow instructions. I always tell parents that if you’re going to give your kid a sparkler, have a bucket of water handy. Make them put each sparkler in the bucket before they can grab another one.
There you have it, folks. This 4th of July, remember Ray and all that goes into making sure you have a safe and spectacular holiday.
Happy birthday, America.