The Weller irons use a resistive tip to generate heat. By varying the power through the tip, the temperature can be controlled. The Metcal uses an inductive tip that is tuned to be at one temperature. | The Weller irons use a resistive tip to generate heat. By varying the power through the tip, the temperature can be controlled. The Metcal uses an inductive tip that is tuned to be at one temperature. |