Disclosed is a method of forming a heat exchanger turbulizer apparatus including a member having a longitudinal axis, a lateral width and a plurality of strips including first strips and second strips, each strip extending widthwise and being corrugated longitudinally so as to form a plurality of laterally spaced-apart sections connected to one another by bridges projecting from the sections in a common direction, the bridges of the first and second strips extending in the same direction and the corrugations of the second strips being offset laterally from the corrugations of the first strips. The method comprises: crimping longitudinally-corrugated strip material between first and second forming dies to form said apparatus, said dies being adapted such that substantially all lateral movement of strip material in crimping results from strip material being drawn laterally by material that has been displaced in a direction parallel to the direction of die movement.