PTFE Film: Powder Rolled Thin, a Minute at 400 °C, Quenched (Brubaker & Hanford 1946)

Fed between two smooth rolls set 1–2 thousandths of an inch apart, PTFE powder comes out as a fragile film. One minute in a furnace at 400 °C and a dip in cold water turn it into a tough, flexible film. Rolling it again cold makes it stronger and clearer. Source: M. M. Brubaker and W. E. Hanford (du Pont), US 2,400,099 (1946), Example III. The furnace and quench bucket are ours. Picture drawn by Youblob.