The present invention relates to an improved resistance weld-based gun assembly for use in an electric welding system without a need for plant-provided air and water-cooling circulation systems. In one aspect of the invention, a resistance-based force controller measures the resistance of a secondary circuit of the weld gun, the combined resistance of the secondary circuit in parallel with the circuit formed by the workpieces and opposing electrodes when sandwiched between the electrodes, and calculates the resistance of the workpieces. The measured resistance is compared to a predetermined resistance and the sandwiching force of the electrodes incrementally adjusted until the resistance of the workpieces is acceptable. The invention also relates to a closed loop coolant system having a coolant line, a coolant contained within the coolant line, a heat exchanger, and a mechanical coolant pump. One possible pump comprises an elastic bladder dependent upon the state change of the coolant. A second possible pump comprises a reciprocating extractor mechanically connected to the weld gun actuator. In yet another aspect of the invention, the welding system relies solely on electrode arm material for heat dissipation, the heat being conducted through the electrode arm material to an outer surface of the arm where the heat is dissipated through natural convection. To promote natural convection, a plurality of ribs with channels defined therebetween or openings extending through the arm itself increase the surface area and the rate of convection.