A method of making a heat exchanger that includes providing a plurality of tubes. Each of the plurality of tubes has exterior cladding on an exterior surface, interior cladding on an interior surface, and a weld seam extending along the length of the plurality of tubes. The method further includes arranging the plurality of tubes such that each of the plurality of tubes is inserted into a corresponding header slot with the weld seams of each of the plurality of tubes oriented downward with respect to gravity, and brazing each of the plurality of tubes and the header after each tube has been inserted into a corresponding header slot. The brazing causes the interior cladding to melt and pool inside the plurality of tubes and along an interior side of the weld seams to form a clad cover portion encases debris generated while forming the weld seams.