Well as a museum you need to be careful that you don't become a social enterprise that is for the good of the public masking as a nonprofit museum. If you have a leadership group (paid usually) that runs your museum like a business or with business practices you have a social enterprise with free volunteer labor. Certainly money at any museum is always an issue and will always continue to be. So fund raising is and always will be a vital part of a museum success. But if the leadership group is running your museum with little or ineffective input and /or direction from its members or just does as they want you will continue to have issue with volunteers feeling a part of any org. If you are experiencing issues with recruiting new members, especially the young variety, having to struggle to find train crew fill other activities and a paid staff that keeps growing. You may have more of an issue than just getting volunteers to just come out and stop of their criticizing. Ask yourself who your museum is being run for the Volunteers and what they are interested in, for the good of the public or your paid staff / leadership group. There is one wrong answer there find that and that should answer most your questions Marty.