Why is using an air chisel to remove a door skin not advisable?

Using an air chisel to remove a door skin is not advisable primarily because it could cause too much damage to the hem flange. The hem flange serves an important structural purpose in a door, as it provides strength and rigidity to the frame. When an air chisel is employed, the force and vibration can easily compromise this flange, leading to warping or structural failures of the door.

Moreover, damaging the hem flange can result in a door that does not fit properly when reassembled or reinforced, which could impact its functionality and longevity. Therefore, selecting a removal method that minimizes the risk to the hem flange is essential for maintaining the integrity of the door. While the other options touch on relevant issues, they do not address the critical structural concerns associated with compromising the hem flange.