19. Oven-baked Lab-metal sands quick ’n’ easy. Realistically, these are framerails, so this bit o’ filler work need not be laser-straight—just smoothed-over without hammer marks. 80-grit 3M Gold Stikit on a 6-inch DA (dual-action) sander faces off the high spots. Taking care not to undercut, we’ll switch to 120-grit and repeat.