After airbrushing it and waiting for an hour, I tested an inconspicuous spot and test it if it is dry. It scratched easily. It's like when you're scratching paint with your bail, and it all got wrinkly, as if it didn't get dry.
How long is Tamiya supposed to dry, before painting another different color (I painted the part white, and I wanna add some red in the same part.)?
*Edit: I just woke up this morning, and did a scratch test. The paint did not scratch at all, and feels dry.