I was surfacing some rough poplar yesterday with my drum sander. The boards had been band sawed from the log and, naturally, they were quite rough and the saw blade marks were obvious. A few passes through the sander and all was nice and smooth but the location of the band saw marks was still evidenced by lighter colored stripes about 1/4" wide and at about 1" intervals across the board. Further sanding and they disappeared but they were at least 1/16" deep.
I should say that once the board was smooth, the stripes differed from adjacent wood only in color...no disruption of wood fibers, I looked with a
10x glass.I've seen this before but never on anything except poplar and then on only the sap wood, never on heart wood. Anyone have a clue as to what causes it? The only things that come to my mind are heat and/or pressure from the blade but I wouldn;t think that would/could cause the regular interval of the stripes.