It has been almost two years since Scottish Opera's orchestra officially went part-time.

That deeply controversial move marked the end of long and messy contract negotiations between management and musicians; in practical terms it came down to money, but the wider public debate went to the heart of whether and why Scotland needs a publicly funded opera company, and what the key ingredients of that company should be. Many people (quite reasonably) argued that it's the singers that crown an opera company, but Scottish Opera hasn't kept soloists or chorus on its staff for years. Others argued for the orchestra: without a signature house band, what artistic stamp remains of the company?

I say "officially" part-time, because even before their contracts were chopped the orchestra had been under-used by a company that could no longer afford to stage a full contingent of productions each year. The final cut consolidated worries about the future of Scottish Opera as a whole, and the future of the individual musicians set to lose half their salaries. Could the orchestra keep standards up despite low morale and a reduced rehearsal schedule? Would the musicians be able to supplement their part-time contracts with freelance work around Scotland, and what would be the knock-on effect on other freelance musicians? Would the orchestra's top talent leave the country altogether in search of full-time positions south of the Border?

Some musicians did drift away, and those who stayed had to think long and hard about how they were going to pay the bills. The Musicians' Union commissioned a report that looked at whether there might be ways for the orchestra to do more work outside of their 28 contracted weeks with Scottish Opera.

"Many of us in the orchestra had been saying for years that we'd like to do more work," says violinist Katie Hull, assistant leader of the Scottish Opera orchestra. "We always felt we could be better used, but the company couldn't find ways of incorporating us other than its main-stage productions. There was a long period when the orchestra was being paid full-time but wasn't working full-time, but that wasn't for a lack of us thinking 'we should be doing more'. So when we were made part-time we thought, 'maybe this is our chance to do some of the things we've been suggesting to management all along.'"

One of the authors of the MU report put the orchestra in touch with Co-Operative Development Scotland, who suggested they could form a self-governing co-op. With no management structure and off-the-peg legal documents it was an attractive model and last spring the orchestra voted for a committee of members to write a constitution for Music Co-OPERAtive Scotland, or McOpera.

The framework is fairly simple. Members pay £100 to join and are then offered freelance gigs booked through the co-op – anything from a solo slot at a wedding to a full orchestral concert. Each musician is paid a set fee for the work and McOpera takes 10-15% on top. Any profit goes back into the co-op, most likely to be spent supplementing orchestral concerts down the line.

It may seem simple, but transforming 50-odd orchestral musicians into hardened business minds is not. "It's been, well, a challenge," Hull tells me, with a laugh. "As musicians we don't necessarily have much business acumen - I tend to think of anyone I meet as a friend or a colleague, not someone I might be able to get something out of. It's been a massively steep learning curve."

But with a £10,000 start-up grant from Scottish Enterprise and some sturdy business advice, McOpera has been up and running since October and launches its first concert series this Sunday. Three chamber concerts at St Andrew's in the Square aim to "introduce" the sections of the orchestra: the brass kick off with a mediaeval-to-modern showcase this week; the strings play Bach (including Brandenburg Concertos No 3 and 5) on March 17; and on May 19 the winds play Mozart's Gran Partita and Dvorak's Serenade op 44.

The idea, says Hull, is "to introduce the musicians up out of the pit, and out of a big clump of players. The co-op is about letting us be individuals rather than 1/50th of an orchestra. We've been able to think about how we want to connect with the audience, what kind of performance etiquette we want to keep and what we can ditch. All that has been pretty liberating actually."

Ultimately McOpera aims to present whole operas – not fully staged (too expensive), but using alternative spaces and digital visuals. For now they're focusing on earning money. Weddings and corporate events, the kind of bread-and-butter gigs that many freelancers rely on, are top of the list. Last weekend members of the co-op could be found manning a stall at the Scottish Wedding Show at the SECC – "probably not what we dreamed of when we were at music college," Hull admits, "but this is the reality faced by many musicians these days".

It's been a case of painting their own silver lining onto a pretty dark cloud. Hull says she and her colleagues have been forced to be much more flexible about how and where they work than previous generations were. And yes, the co-op has injected positive energy into the pit of Scottish Opera. "It's been a lesson in coping and adapting, and a really good chance for us to channel our energies. It's made us think about taking charge of our own lives."

The old worries still hang over the Scottish Opera pit, though. Even new players brought in to replace those who left keep one eye on openings for more secure work elsewhere, so there's a sense the orchestra won't be able to recruit top players. And there's the question of maintaining standards.

"An orchestra only gels if it works together regularly," says Hull. "You get better results from an orchestra that's used to playing together rather than a freelance group, no matter how good the freelancers. A regular orchestra has a sort of sympathetic understanding of itself –it's extremely difficult to get that cohesion if you're not working together week-in week-out."

McOpera hopes it can bridge the off-weeks in Scottish Opera's reduced schedule and keep up a cohesive sound and identity. But with three other orchestras and plenty of freelancers in Scotland already, how much work they can create remains to be seen.

McOpera brass perform at St Andrew's in the Square, Glasgow, at 3pm on Sunday. www.mcopera.com