Stitch Welded Elbows are galvanized metal elbows that are stamped out using mechanical presses and forming dies. Tubed Duct Elbows are an excellent choice for paper trim and oil mist applications, because they have no seam. Instead, these elbows are mechanically bent, resulting in a non-seamed tubing that can be fitted with a rolled-lipped collar or an angle ring flange.