Steelhead Compositesmakes bottles/liners/cylinders with a process called metal spinning or spin forming, a hot forming process that rotates a metal tube around its central axis (similar to a lathe), softens the material by adding adequate heat, and then forms the material to its final shape using a roller. Our spinforming process begins with an extruded tube and does not use a mandrel, sometimes referred to as “free air” spinning. There are many other applications of conventional spinforming where a flat sheet of material is formed against a mandrel. Those techniques differ from free air spinning, but all rely on similar principles. One technique we use is x-y spinning. This technique pushes the roller into the blunt cut edge of the tube, forcing the tube material to reduce in diameter as the roller is advanced. This approach works well with aluminum. Most of Steelhead’s domed vessels are formed through oscillating spinning. In this approach, the roller contacts the tube, away from the cut edge, then rotates downwards along a defined path, drawing outwards towards the cut edge. This motion deforms the tube into a dome shape with a defined neck diameter. This process is suitable for almost all ductile metals, including stainless steel.