Geoff:
Volunteer retention is a very common problem among nonprofit organizations. There is an enormous pool of potential volunteers out there, but in spite of your best efforts you just can't seem to net many of them: they just slip through your fingers. Why aren't these new volunteers as excited as you are about working on bicycles?
Years ago I attended a very compelling session on the topic of volunteer retention, at Bike! Bike! Los Angeles. My takeaway was that if you want to retain volunteers, you have to understand why they have chosen to volunteer. As different people volunteer for different reasons, you have to understand and address each of their individual needs.
For example, people who show up on their own often are there to make new friends. People who come in groups organized by an employer might generally be there to get time off of work or gain favor with the boss rather than to repair bicycles.
In some shops a group of new volunteers shows up in the morning and is immediately put to work. Other shops require new volunteers to endure an official orientation session where all of the shop procedures are explained in detail. How do you onboard new volunteers?
I like Alison's technique of asking volunteers what motivated them to volunteer. All of your regular shop volunteers should think of themselves not as bike mechanics, but rather as recruiters building a cult centered on bicycles. Ask new volunteers why they are there, and try your best to deliver what they want.
Even among people who have a passion for donating their labor in service to others, there are different aptitudes and skill levels. Some have never held a wrench. Others already know a lot from repairing their own bicycles at home. Onboarding new volunteers requires specific personal attention. If you walk everyone through the same basics, some in the audience are going to be bored out of their minds, while others will be in over their heads.
My own feeling is that a 1-hour induction program is overkill. Most people like to be doing things rather than being told things. Depending on how it is delivered, having to sit through one hour of talk could suck all the positive spirit out of even the most ardent volunteer, as you drone on about mission statements, shop policies, etc.
My preference is to start out the day with just a few brief remarks on your mission as an organization. Then I like to pair up new volunteers with veteran bike mechanics for some small group hands-on work. Show someone how to do something new, and let them try for themselves. Make them feel useful and valued. All your new volunteers can reassemble, perhaps at a meal or break time, for additional brief lectures about shop organization and procedures.
It may not be clear to you, but not everyone has the talent to successfully onboard new volunteers and convert them into valued regular volunteers. This task requires knowledge about bicycles, but also important people skills and enthusiasm. While successful onboarding is a responsibility for the entire shop, the person you choose to lead this vital activity is crucial to your shop's success in growing its volunteer base. You need to be very conscious of this, and carefully select/train people to create a successful onboarding program.
One simple yet effective technique is that when a new volunteer leaves the shop at the end of the day, have a greeter interact with them. Thank them for coming. Ask them about their experience, and whether it met their expectations. Tell them how happy you are that they came to volunteer, and that you hope they will return at the next volunteer event. Bonus points if you can call them by name, but you can make it easier by providing name tags.
I am a big believer in metrics and surveys. You can't know how well you are going at onboarding, without having a way to measure your success or failure rate. Ask every new volunteer to sign in with their name and contact information (phone number, email, or mailing address). In addition, ask every returning volunteer to sign in and record the number of hours they volunteered. Periodically, someone looks at this information to determine the number of new volunteers who ever returned for a second or third time.
You should also poll your own existing volunteer base. Ask your regular volunteers what drew them to your shop, and what made them return. If a new volunteer returns several times, ask them what they liked, and how you can improve the onboarding experience. If a new volunteer only comes once or twice and then stops, reach out to them to ask them about their experience, and why they haven't returned. It helps to have many specific questions regarding various aspects of the onboarding experience, to help people understand what you are getting at and how to organize their feedback, versus asking, "Well, what do you think?"