A form of resistance butt-welding, generally used on stock that is wide and thin; sometimes advisable when the welding faces are not cut square and true. It is also used in welding tubing to tubing. Flash welding is used in cases where a small amount of stock is to be taken up in the weld, or when the specification is to shear or grind off the fin. The space between the clamping jaws of the butt welding machine is never more than the diameter of the stock when making a flash-weld; generally it is only 70% of the diameter of the work. See FLASH WELDING and RESISTANCE WELDING.
