We build things in America again. But not just anything.

The U.S. manufacturing sector, once a vast network of assembly lines churning out every imaginable product, has evolved into a specialized and highly efficient industry focused on goods that can’t be built cheaper or better someplace else. There are good jobs in manufacturing — the kind able to finance a comfortable middle-class lifestyle. But there are far fewer than there used to be, and many workers who might have been qualified to man an assembly line 25 years ago lack the skills manufacturers require today.

A recent survey of manufacturing firms by Accenture (ACN) found there’s a “severe shortage of manufacturing skills in the United States.” Only about 20% of manufacturing jobs now are unskilled positions any able-bodied worker can fill. The rest require vocational training, an associate’s degree or certifications that can take years to acquire. Accenture and other analysts say there’s a particular shortage of welders, electricians, machinists, press operators and metalworkers, which means people in those fields enjoy something unusual in today’s economy: strong job security and the ability to command decent pay.

The shortage of skilled manufacturing workers is partly due to the sharp decline in U.S. manufacturing during the past 15 years. That led many high schools to axe vocational programs, while teenagers and their parents began to see college as the only likely pathway to a middle-class lifestyle. But manufacturing has begun to bounce back since total employment bottomed out in 2010. There are now about 12.1 million manufacturing workers in the United States, with some forecasters expecting a broader resurgence due to low U.S. energy costs, rising labor rates in other countries and the higher skill levels required to work with robots and computers. “You don’t need to go to college to make a lot of money,” says Vicki Holt, CEO of Proto Labs (PRLB), which specializes in the rapid production of parts for other manufacturers’ prototypes. “You can go to a two-year school and be making $80,000 by the time you’re 21.”

That’s no cakewalk, however. Here are six things required to get a good manufacturing job these days:

Ability to pass a drug test. America must be Stoner Nation, because this seemingly simple requirement eliminates half of all applicants for manufacturing jobs, by some estimates. Manufacturing often entails work with dangerous equipment in a demanding factory setting, which is why failing a drug test can be grounds for dismissal. That includes marijuana, even in Colorado and Washington, where it’s legal. Manufacturing firms are also unlikely to tolerate slackers who slow down the workflow. And the decline of unions means there are fewer protections when a company wants to get rid of an undesirable worker.

Twelfth grade math and English capability. Working with the computerized equipment in many factories requires an understanding of algebra and the ability to do basic computations. Manufacturing workers increasingly operate as teams, making it important to communicate effectively. “These skills aren’t super difficult for somebody going through college or technical school, but they’re not always being mastered at the high school level,” says Art Wheaton of the Worker Institute at Cornell University. That’s one reason manufacturers prefer a high school diploma over a GED certificate — performing well in high school matters more than simply graduating. Workers who performed poorly in high school — or failed to graduate — might want to look for a job in construction, which tends to have more room for lower-skilled workers than manufacturing does these days.

Dependability. The ability to show up for work on time — every day — is another quality that’s surprisingly uncommon. That’s why a low-paying job flipping burgers or manning a cash register can help land a better job in manufacturing. “Working at McDonald’s may actually prove you can work with other people and show up every day,” Wheaton says. “For the employer, that’s better than getting people who will work for a few paychecks and say, ‘This isn’t fun, I want to go somewhere else.’”

Vocational training or better. A dependable, drug-free high-school grad might earn $10 to $15 per hour at an entry-level manufacturing job, with pay rising along with more experience and on-the-job training. But pay will obviously be higher still for workers who show up with specialized training or certifications. The trick is figuring out what training to get, since most technical schools don’t guarantee a job after charging hundreds or thousands of dollars in tuition. (Of course, most colleges don’t either.)

Some big companies, such as General Electric (GE), Siemens and Caterpillar (CAT), partner with specific training programs or trade schools to keep a supply of needed workers flowing. “The skills you learn may not be directly transferable, but they show you’ve learned,” says Hal Sirkin of the Boston Consulting Group, which predicts a surge in U.S. manufacturing by 2020.

The Georgia Trade School in Kennesaw charges $8,000 for a four-month welding program and often places grads with employers such as Caterpillar and shipbuilder Huntington Ingalls (HII), where pay can start at $20 per hour or so; some workers start with a $1,500 relocation bonus. Good employers usually offer additional training that can push pay to $40 per hour or more within five years. Welders willing to go where demand is highest — such as Houston or North Dakota — can earn more than $100,000 per year.

Familiarity with manufacturing. As with any profession, workers interested in a manufacturing career should research what they’re getting themselves into. Ryan Blythe, executive director of the Georgia Trade School, says the school encourages every applicant to thoroughly research welding before plunking down a tuition check: “Understand you’re going to be working outside a lot of the time. Not many shops are air conditioned. It’s very hard work. If you want to make big money, you’ll probably have to travel or relocate.”

Manufacturing may also offer opportunities talented workers are unaware of, since the sector is often neglected by guidance counselors and others steering young workers toward trendier professions such as tech and healthcare. Holt of Proto Labs, for instance, says her firm is aggressively hiring software engineers to help with computerized protoyping — white-collar jobs that might appeal to college grads who enjoy building things and don’t want to get caught up in Silicon Valley’s egomania.

A willingness to forgo college. The types of high school students likely to do well in manufacturing — strong performers with a good work ethic — also tend to be good candidates for college. Yet a recent decline in college enrollments suggests more young people are balking at the high cost of college, the heavy debt load that can last for years and the uncertain prospects all that money buys. For determined workers, manufacturing may once again be a worthwhile alternative to college. America will be building things for a while.

Rick Newman’s latest book is Rebounders: How Winners Pivot From Setback To Success. Follow him on Twitter: @rickjnewman.