An improved method for manufacturing a heat transfer assembly particularly useful as a component of a radiator used to remove heat from the coolant of an internal combustion engine. The heat transfer assembly includes a plurality of louvered fin strips having fold edges that are in heat transfer contact, through solder joints, with flat-sided tubes designed to carry the fluid to be cooled by a flow of air contacting both the exterior surfaces of the tubes and the fin strip surfaces. The improved method involves the application of beads of solder to the fold edges of the fin strips, rather than to the tubes as in the prior art, before assembly of the fin strips and the tubes. The improved method reduces the amount of solder required and thereby reduces manufacturing cost.