Thomas Edison. Thomas Alva Edison (February 11, 1847 â October 18, 1931) was an American inventor and businessman, who has been described as America's greatest inventor. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and the long-lasting, practical electric light bulb.
Pipe dope, or pipe joint compound, is a gooey compound used to seal the connection between threaded pipes and fittings. Because the threads in pipes and fittings still leave an air gap between the two surfaces, the gap must be filled to make it water tight (or gas tight for gas lines).
Two variants are HDPE (high-density polyethylene) and the more heat resistant PEX (cross-linked polyethylene). PE has been used for pipes since the early 1950s. PE pipes are made by extrusion in a variety of sizes dimensions. PE is lightweight, flexible and easy to weld.