The correct current, or amperage, setting primarily depends on the diameter and type of electrode selected. For example, a 1/8 in. 6010 rod runs well from 75 to 125 amps, while a 5/32 in. 7018 rod welds at currents up to 220 amps. The side of the electrode box usually indicates operating ranges. Select an amperage based on the material's thickness, welding position (about 15 percent less heat for overhead work compared to a flat weld) and observation of the finished weld. Most new welding machines have a permanent label that recommends amperage settings for a variety of electrodes and material thicknesses.