Abstract: A heat exchanger of the plate fin and tube type and a method for manufacturing such an apparatus. The heat exchanger has a curved face as may be required due to the dimensional constraints of the enclosure housing the heat exchanger. The heat exchanger is constructed with single row plate fins in those portions of the heat exchanger that will experience relative motion between adjacent tube rows during bending of the tubes to achieve the curved face. Multiple row plate fins are used in those portions of the heat exchanger where there will be no relative motion between adjacent tube rows during tube bending. A locking member affixed to one tube row receives an end of a tube in an adjacent row that is more inward, with respect to the center of curvature, during bending and secures the two tube rows together. The use of multiple row plate fins and the locking member produce a strong and rigid assembly.