How do I disable self-join on a trello team board that has it enabled?

[Erich Keil]

I made a trello board team visible, and when given the option allowed team members to add themselves to the board. I would now like to disable self-join for that board but don't see an option to do that anywhere. Making the board private and then team visible doesn't ask the self-join question again, it retains the previous settings. Changing it from the team and back didn't retrigger the option either. Please help, I'd like to control who does and doesn't get added to the team visible board as an editing member without having to recreate the board from scratch. 

[Erich Keil]

Nevermind, found it.