Abstract: A method of constructing discrete tubular components (10) for a heat exchanger (50) includes providing a tube portion (12) having substantially flat sides (14). Additionally, a metal strip is provided which includes a substrate material (32) and a second material (34) different than the substrate material forming a layer in the strip. The second material (34) is provided on only one side of the metal strip. The strip is configured in repeated folds of peaks and troughs to form fin portions (16). The tube and fin portions are assembled to form an array (37) of multiple bundles of one of the tube portions with the fin portions (16) arranged on the substantially flat sides (14) of the tube portion (12) and the second material (34) of the strip facing the tube portion (12), and one or more spacers (38) disposed between adjacent bundles. The array (37) is heated to bond the second material (34) to the tube portion (12) in the region of the troughs of the fin portions (16).