Both electrodes focus current at the same point to make a spot weld. Draw a high current for spot welding, according to the thickness and type of medal. Spot welding may require up to 90,000 amperes for thick pieces of aluminum. Maintain the current for a specific period of time.Weld times in spot welding can vary from 0.01 seconds to 0.63 seconds, depending on the metal thickness. Spot welding may be used on extremely thin pieces of metal, up to 1.25-inch metal plate.oth electrodes focus current at the same point to make a spot weld. Draw a high current for spot welding, according to the thickness and type of medal. Spot welding may require up to 90,000 amperes for thick pieces of aluminum. Maintain the current for a specific period of time.