WATERLOO -- Passionate pyrotechnicians say the love affair usually begins with a loud bang and blinding lights.

That's how Dr. Bryan Sands, a dermatologist, first fell for fireworks as a boy. And as often happens when young love strikes, sparks flew.

Today the good doctor is preparing for his first national fireworks show this August in Fargo, N.D. He's competing at the novice level at the Pyrotechnics Guild Internationals competition, but that doesn't matter to him.

"This'll be my first year. I'm really excited," he said.

What draws Sands and his mentor Jerry Dixon, an engineer at Viking Pump, is much more than the sexy booms and explosions of fireworks. Both know and enjoy chemistry, which plays an essential role in fireworks.

Chemical compounds are what give fireworks their color and shape. Use copper and blue colors will fly from exploding shells, while barium nitrate will create greens. A sugar is used as a glue to hold different pieces of a firework in shape, which is what allows fireworks to explode in star shapes on July 4 shows. Silicon powder is inserted into fireworks to speed reactions, which allows fireworks to explode at just the right time in the air.

For card-carrying pyrotechnicians -- you need to pass an exam to create fireworks and put on shows -- finding the right mix of ingredients is the most challenging aspect of the hobby, and is considered an art (people who build a show are often called artisans).

Dixon said the recipes, or formulas, for fireworks are often closely-guarded secrets. The copper compound to create stunning blues is perhaps the hardest to create, and old Italian shell builders kept their formulas locked in a safe.

"It's just a variation of gun powder, but by changing the percentages of what you put in there, you can get whistling effects, crackling effects, all kinds of color effects, color changing," Sands said.

Fireworks is not for everyone. Because of its explosive nature, it is highly regulated. Beyond obtaining a pyrotechnician license, Dixon creates and shoots fireworks at a federally licensed facility that also meets state and local regulations.

"There are some ingredients that you don't mix together or bad things happen," Dixon said. "That's where your chemistry come in."

A helpful hint: don't mix potassium chlorate with sulfur. The wrong mixture, a finger scratch, a dropped shell or even static electricity can set fireworks off. The danger static electricity poses is the reason Dixon and Sands don't work on fireworks in the winter.

Another obstacle to the hobby is price. A 12-inch shell (city shows typically use 4- to 8-inch shells) is full of $50-worth of ingredients, and sells for a couple hundred dollars commercially. Take into account the several test runs needed to find the right mixture, and the cost of just one firework, much less an entire show, quickly adds up.

All the time and expense required to create a show is made worthwhile when a pyrotechnicians hears the "ooohs" and "aaahs" from the audience. Like a sports star or musician, they live to share their passion with others.

Ellen Neebel, who works claims at Dermatology Associates where Sands practices, watched Sands' 20-minute show last summer.

"I remember them being a spectacular display of fireworks. I just didn't expect the size of them. I mean, you would have thought it was put on professionally," Neebel raved.

Contact Jens Manuel Krogstad at (319) 291-1580 or jens.krogstad@wcfcourier.com.