A system for forming a weld nugget in a metal work piece includes a power supply, actuator, electrodes, and controller. The actuator delivers a variable electrode force to the work piece in response to a force command. The controller executes a method by transmitting a welding current command to the power supply to cause the power supply to output a welding current to the electrodes. The controller transmits the force command to the actuator to apply the variable electrode force, via the electrodes, to the work piece at a first force level. The variable electrode force increases from a second force level immediately upon conclusion of a first duration to minimize weld expulsion. The second force level commences at a point in time in the dynamic resistance profile at which a dynamic resistance value of the work piece decreases at a threshold rate during formation of the weld nugget.