Yup, tear out. Like Michael said, walnut dust may have made it stand out more. It is pretty much impossible to get all tear out gone since every bowl that is side grain will have you going against the grain 2 times each revolution. Generally you can feel it with your fingers before you start sanding. I use a shear scrape to remove it, and that is one video I did. My preference is for a burnished burr on a scraper, and the higher the shear/sheer scrape angle is, the cleaner the cut. The idea with a shear scrape is to reduce the tear out to where it will take minimal sanding to get rid of it. I am something of a scraper psycho, and use them more than most. I would never use a standard scraper on a bowl or a plater for finish cuts, other than for sweeping across the bottom of the bowl. In the transition and up the sides may work with some woods, but they still leave tear out because scrapers tend to pull on the wood fiber more than a gouge will. You can lightly spritz the area with water and that helps lubricate the fibers for a cleaner cut. Don't know about the sanding sealer. When all else fails, start with 80 grit. Big leaf maple never seems to cut clean, and a lot of the time, I have to start with 80 or 100 grit. Most other woods, I am starting at 120. As for a negative rake scraper, it is still a scraper, and it still pulls at the fibers. As always, it works better with some woods than with others. With end grain pieces, like boxes, I can get surfaces that look better before I try to sand.
robo hippy