A method for fastening a first electrically conductive material to a second electrically conductive material using electrical resistance welding, comprising: - placing the first and second materials together in physical and electrical contact, the first material having a lower melting point than the second material, the first material including at least one of aluminum, copper, magnesium and alloys thereof, the second material including at least one of steel, titanium, alloys thereof and Inconel; - placing an electrically conductive fastener that has a higher melting point than the first material in physical and electrical contact with the first material to form an electrically conductive stack inclusive of the fastener , the first material and the second material, the fastener is symmetric about a rotational axis having a cap portion and a hollow shaft portion , the cap extending from the shaft at the open end of the U-shape forming a downwardly directed peripheral lip, the fastener being made from at least one of steel, titanium, alloys thereof and Inconel and/or from at least one of stainless steel, aluminum alloy, magnesium alloy, copper alloy, titanium alloy and Inconel; - applying an electrical potential across the stack, inducing a current to flow through the stack and causing resistive heating, the resistive heating causing a softening of the first material; - urging the fastener through the softened first material toward the second material; - after the fastener contacts the second material welding the fastener to the second material; and - capturing first material displaced when the fastener is urged through the softened first material and welded to the second material, the displaced material being captured within the peripheral lip of the cap portion of the fastener , and the displaced material further being at least one of an upwelled first material, or an upwelled first material and intermetallics, wherein the method further comprises stamping the fastener from a sheet prior to the step of placing the fastener . - placing the first and second materials together in physical and electrical contact, the first material having a lower melting point than the second material, the first material including at least one of aluminum, copper, magnesium and alloys thereof, the second material including at least one of steel, titanium, alloys thereof and Inconel; - placing an electrically conductive fastener that has a higher melting point than the first material in physical and electrical contact with the first material to form an electrically conductive stack inclusive of the fastener , the first material and the second material, the fastener is symmetric about a rotational axis having a cap portion and a hollow shaft portion , the cap extending from the shaft at the open end of the U-shape forming a downwardly directed peripheral lip, the fastener being made from at least one of steel, titanium, alloys thereof and Inconel and/or from at least one of stainless steel, aluminum alloy, magnesium alloy, copper alloy, titanium alloy and Inconel; - applying an electrical potential across the stack, inducing a current to flow through the stack and causing resistive heating, the resistive heating causing a softening of the first material; - urging the fastener through the softened first material toward the second material; - after the fastener contacts the second material welding the fastener to the second material; and - capturing first material displaced when the fastener is urged through the softened first material and welded to the second material, the displaced material being captured within the peripheral lip of the cap portion of the fastener , and the displaced material further being at least one of an upwelled first material, or an upwelled first material and intermetallics, wherein the method further comprises stamping the fastener from a sheet prior to the step of placing the fastener . <EOS>