I bought a $50-$60 hot air rework station on ebay, im trying to learn micro soldering and when I try desoldering a random chip on a board, it wont come off, I seen youtube videos saying that when using 350 degrees temperature the chip should come off within 30sec, not working with me, not even after 2min. is the problem due to the cheap rework station? note: im also not using flux as atm don't have any.
The time to remove a part depends on the thermal mass of the board it is connected to and the power (temperature and flow rate) of the hot air. If you have a chip connected to a big ground plane, it can take a long time to remove, especially at lower airflow. 2 minutes is not unreasonable, especially for a lower power hot air rework station, a big ground plane and lead free solder.