Natural Rubber Tubing, Bands and Sheet: Sulfur-Cured with Heat

Raw rubber goes soft and sticky when warm; mixed with sulfur and heated it cures firm and elastic (Goodyear, 1839; Hancock's patent, 1843). Mill smoked sheet with sulfur, then either press it flat and cure it as sheet, or extrude it as a tube, cure the tube on a mandrel, and slice it across into rubber bands. The picture: our diagram of the three products.