When physics teacher Chris Pearce left his job as vice-principal of a sixth-form college to run two flourishing fireworks companies, he knew he'd be stereotyped as a mad classroom scientist.
"But it wasn't like that at all," says Mr Pearce, 37, an effervescent Methodist lay preacher who got his masters in applied radiation physics at Birmingham University.
"I'm not in the least eccentric. At the Mander Portman Woodward College in Edgbaston, I was immersed in the very rigorous physics teaching of small groups anxious to get an A-levelor improve their grades. No sparky experiments at all."
He had always been fascinated by pyrotechnics and after encountering the company which created the VJ Day display on the Thames, he started his first business as a hobby 10 years ago.
"There are so many legal and safety requirements that, eventually, I found I couldn't do both jobs," he says.
It proved a good move. His Jubilee Fireworks company at Tipton in the West Midlands is turning over pound;330,000 a year, while a sister company imports fireworks from China.
He was pleased that his company took part in the recent National Fireworks Championship in Plymouth. Although unplaced, it stood up well against big companies.
Mr Pearce has not entirely left teaching behind. He writes articles on the physics of fireworks and is always happy to give talks.
Although the company's busiest time is in the run-up to November 5, operator-controlled displays at up to pound;1,000 a minute keep the business going over the summer.
A 12-minute display for an outdoor event can take six people a week or more to engineer. "We don't manufacture the fireworks, but we fuse them individually and link them to a control panel using hundreds of feet of cable."
The biggest annoyance of his new career is "the utterly foolish lobby that wants to see fireworks banned".
"When I was a boy, I could buy a box of penny bangers, but if I tried to sell one now I'd be breaking the law. Yet there is nothing to stop me from selling very high-powered display rockets to anyone who wants one.
"Every reasonable precaution has been taken to restrict access to fireworks to people over 18. The number of accidents is really very low. It will be a sad day when people can't let off their own fireworks."