TinkerTank works at all hours - we have robotics teams that meet until 10pm at night, and groups that start at 7:30 in the morning. We're a small business, so 99% of the time, it's either Julija (the founder), or Kendall (me!) in the space, doing a day from 7:30am - 8pm.
If you want to pop in and say "hi" - Saturday 10am - 1pm we're open for visits. Outside those hours, it's safe to assume we're teaching, or in meetings. It's generally not an opportune time to pop by.
The best policy? If Saturday doesn't work, questions? Email: Info@tinkertank.com.au and ask when a good time to come in.