Benghazi, Libya (CNN) -- Two months ago, Massoud Ojeli was in college, studying English -- but now, he works at a secret makeshift weapons factory in Libya, welding together spare parts to make arms for the country's opposition forces.

"It's a very weird feeling, but I'm proud of this," the 20-year-old Ojeli says with a smile, in between his work crafting rocket launchers in a hot concrete warehouse space in the rebel stronghold of Benghazi.

The rebels granted CNN rare access to a place where elbow grease and ingenuity turn damaged and dented old weapons into rough-and-ready killing machines.

About 200 men volunteer at the factory, arriving around 8 a.m. and leaving around 3 p.m., when the sun is hottest over the dusty landscape.

They don't get paid, but there is no shortage of help. Ojeli's father volunteers at the factory, too, and his two little brothers hang around to offer moral support.

"I do this for my country," Ojeli says.

Many of the men are soldiers who have defected from the regime of Libyan leader Moammar Gadhafi, but others are newcomers.

Asked whether he knows what he's doing at the weapons factory, Rami Tarhouni smiles and laughs.

"I don't have idea," he says. "I don't have idea, but I'm trying."

A few weeks ago, Tarhouni was an insurance agent. Another volunteer, Ali Abdul Salam, was in pharmaceuticals. He flashes a victory sign.

"People who've never seen weapons in their lives are making them from nothing," says Col. Mohammed Algarobelli, who says he defected from Gadhafi's air force.

In one part of the factory is an old weapons pod from an old jet fighter. By the time they're done with it -- if all goes well -- the volunteers will have turned it into 32 shoulder-fired missile launchers.

Elsewhere, Soviet-era rocket launchers are broken up to fit on smaller vehicles like pickup trucks to go to the front lines.

Using whatever they can get their hands on can pay off in a place like this; a panel fitted with household light switches is used to launch the rockets from the back of the trucks. There's never a guarantee of success, however.

"Sometimes we have something that doesn't work," Ojeli admits.

He says if he had his way, Gadhafi would be gone and he could go back to college. Until then, he says, he's keeping his new job.