From the day Scott Sorensen was hired on to the “MythBusters” crew, the mundane moments of his workday became an urban legend.

On his first day on the job in 2007, he was sent to every big grocery store in San Francisco, where he single-handedly decimated the soda supply to make a giant Diet Coke and Mentos fountain.

The next day, he hauled a load of swine carcasses from the East Bay.

“I’ll never forget that. Driving across the Bay Bridge in (co-host Jamie Hyneman’s) little pickup truck with four or five dead pigs in the bed of the truck, uncovered,” said Sorensen, who had responded to the “MythBusters” production assistant job from a Craigslist posting. “I’d look in the rearview mirror with a pig face looking back up at me.”

The Discovery Channel series, which ends after 14 seasons with a two-hour finale and reunion special Saturday, is one of the most successful San Francisco-based television shows in history. Credit goes to popular hosts Adam Savage and Hyneman, and the concept itself: using science to test the validity of urban legends, movie scenes and other myths.

But look deeper into the 278 episodes, and the show prospered because of a group effort, including kindness from strangers, strong relationships with local agencies, and perhaps most of all, an extremely nimble crew.

Key ingredient to success

Before every RV was blown to smithereens, every vessel made out of duct tape was sent out to sea, and every cannon was built to launch frozen chickens, there was a behind-the-scenes effort from this creative and sometimes astoundingly resourceful team.

“It’s impossible to overstate how important the crew was to ‘MythBusters,’” Savage said during an interview last week in his Mission District workshop. “When you have a bond, and it’s genuine, there’s a special magic that can occur. There’s no formula for making a great show. It is an alchemy. But I think one of the key (ingredients) is that everyone who works on it feels the same amount of investment.”

“MythBusters” premiered in 2003 as a small-scale production, created by Peter Rees and produced in Australia but set in San Francisco because special effects industry veterans Savage and Hyneman didn’t want to move from their Bay Area homes.

The budgets and ambitions grew as the years passed — as did the show’s exceptionally loyal audience — but the crew stayed small, starting with nine members and ending with 17 when the show stopped filming last year. Savage said that was intentional, to keep the “We’re all in this together” vibe of a family.

Obtaining the impossible

Hiring was an unconventional process, and many of the crew members stayed for 10 years or longer. Savage said he heard from longtime director Alice Dallow that Sorensen got the job out of UC Santa Cruz, in part because he had tattooed a platypus on his arm — a reference to a student film he made.

“Alice said, ‘That’s what I want. Someone with that kind of commitment,’” Savage recalled.

Legends on the “MythBusters” set don’t just come from the episodes themselves, but also from the efforts of the crew to obtain the impossible. As entertaining as “MythBusters” could be on a good day, there could have been an entirely new reality show covering the behind-the-scenes races against time and logic.

Take this instance during the 2004 season when “MythBusters” wanted to lift a boat using tens of thousands of pingpong balls, only to find that the 80 cents-per-ball price was beyond the show’s budget. So they called on Eric Haven, the show’s producer with a Red-from-“Shawshank Redemption”-style reputation for procuring hard-to-find items on a deadline.

“In the end, we did a deal with a pingpong ball company. But before that, Eric found us 60,000 pingpong balls for free,” Savage said. “The only catch was they were in Japan being used as part of avalanche research, and they were all painted different colors. … Eric found this guy. He was ready to fill two (shipping) containers with pingpong balls and send them to us.”

There was the time they needed 60 pounds of ballistics gel late on a Friday afternoon and found it at a Vallejo forensics lab; workers were willing to drive it to the set. And the time Savage said Linda Wolkovitch, a producer known for her ability to smooth rough relationships, got permission to sink a boat in the protective wildlife sanctuary along the Northern California coast.

Map: MythBusting in the Bay Area Check out an interactive map highlighting some the ‘MythBusters’ favorite and most iconic local filming sites.

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The best “MythBusters” episodes often started with a crew member calling a random source on the phone and making a bizarre request.

“Sometimes they would say no and just hang up,” Haven said. “But sometimes they would react completely enthusiastically: ‘That sounds insane! Whatever you need, just let me know!’ There were people who didn’t even know about ‘MythBusters,’ and they still wanted to help. ‘Yeah, I don’t have a TV, but what you’re doing seems really fun …’”

Building loyalty at locales

Over the years, the show built relationships with a legion of city, county and state agencies based in the Bay Area, frequently filming at Fort Mason, Alameda Naval Air Base runway and, perhaps most memorably, the Alameda County Bomb Disposal office in Dublin. Alameda County sheriff’s Sgt. J.D. Nelson, the Explosive Ordnance Disposal team leader at that site, was one of several local officials who became regular onscreen presences.

There were also memorable partnerships with private vendors, including Mr. S. Leather for bondage gear in San Francisco, the Bone Room curiosity store in Berkeley and East Bay Vivarium. In one episode testing a fear myth, the Berkeley reptile emporium helped to cover cast member Kari Byron with a bucket of scorpions.

“I’ve never met a crew that was more together and more gracious,” said Vivarium co-owner Owen Maercks. “They treated me with a level of respect and camaraderie. I’m very, very sad I won’t be working with them anymore.”

Invaluable education

The feeling is mutual. “MythBusters” crew members said the episodes were an incredible training ground for shooting video and capturing audio, as they constantly prepared for the unexpected. The show was designed so no one knew for sure during any given moment what might happen next.

“Working for ‘MythBusters’ has been great because you can always have a conversation with someone about the last thing that you did,” Sorensen said. “It’s good at family gatherings. ‘Oh yeah. Last week we were in Oregon imploding a train tanker car.’”

“Who gets to do this?” added Matt Jepson, an audio tech who worked on “MythBusters” for 10 years. “We were basically like a bunch of 14-year-olds with a suitcase full of cash, and an MIT professor whispering in our ear.”

There was a high rate of flameout with new hires, Savage admitted, but people who worked out stayed a long time, often advancing quickly. Haven was hired at the lowest level as a runner and ended as one of the show’s five producers. Sorensen started as a production assistant and ended the series as a director of photography.

Discovery Channel announced last year that this 14th season would be the last, allowing an unusual level of closure for a cable television show. The reunion after the hour-long final show includes participation from the crew and former cast members Byron, Tory Belleci and Grant Imahara, who left “MythBusters” in 2014.

With the last “MythBusters” scenes shooting in November, some in the cast are taking time off, while others are working new jobs, including Savage and Hyneman. Among other projects, Savage is working on a new non-“MythBusters” stage show and a short film related to his costuming work. Haven, a comic book writer and artist, is working on a new graphic novel.

Sorensen just got back from a job in Los Angeles, and while he said it was good work, it wasn’t exactly hauling-pigs-across-the-bridge kind of fun.

“Now it’s like, ‘What did you do today?’ ‘Well, I filmed two people talking to each other,’” Sorensen said.

‘These are the good old days’

Jepson said that everyone in the crew had been preparing for this day. He remembers setting a co-worker straight once, when frustration surfaced on the set.

“It’s like, ‘Dude, you’re getting paid to shoot at windows out of a car,’” Jepson said. “I would tell people, ‘These are the good old days. Just know that.’ This will never happen before, and this is never, ever going to happen again.”

Peter Hartlaub is The San Francisco Chronicle pop culture critic. Email: phartlaub@sfchronicle.com Twitter: @PeterHartlaub

“MythBusters”: Finale and reunion show airs at 8 p.m. Saturday on the Discovery Channel.