One plant, Quality Record Pressings, in Salina, Kan., opened in 2011 after its owner, Chad Kassem, grew impatient with delays at a larger plant where his own line of blues reissues was being pressed. His company, which runs four presses — acquired used, but modified to run more efficiently — now makes LPs for all the majors, and lists Jimi Hendrix, Eric Clapton and Nirvana reissues among its recent projects. He is currently pressing 900,000 vinyl discs a year.

“We’ve always had more work than we could do,” Mr. Kassem said. “When we had one press, we had enough orders for two. When we had two, we had enough orders for four. We never spent a dollar on advertising, but we’ve been busy from the day we opened.”

There is a limit to how much the vinyl business can expand right now. When it seemed inevitable that CDs would supplant LPs, the companies that made vinyl presses shifted to making other kinds of machinery. The last new press was built in 1982, so relatively recent start-ups like Quality and Brooklyn Phono searched out used presses (the going rate is about $25,000) and reconditioned them. Most plants have deals with local machine shops to make replacement parts.

Some pressing plants have looked into commissioning or building new presses but have found the cost prohibitive — as much as $500,000, said Eric Astor of Furnace MFG in Fairfax, Va. “Since my partner also owns a CD/DVD plant,” Mr. Astor said in an e-mail, “we’ve been testing using the methods used in disc manufacturing to make a new breed of vinyl record, but that R&D is slow going and not looking promising.”

How are LPs selling? That is a matter of dispute. David Bakula, Nielsen SoundScan’s senior vice president of client development and insights, said that his company tracked 4.6 million domestic LP sales last year, an 18 percent increase over 2011, but still only 1.4 percent of the total market, made up mostly of digital downloads (which are increasing) and CDs (for which sales are declining). This year, Mr. Bakula said, vinyl sales are on track to reach about 5.5 million.