Manufacturing process of safety glass in a glass factory in the United States
Sand rock and silica sand being quarried by blasting and being broken down and cleaned before transporting to a glass plant in United States for manufacturing safety glass. Various raw materials like sand, limestone, soda ash, charcoal and salt cake are put in a furnace, moved about, blown, and afterwards melted to roll out sheets of glass. Location: United States USA. Date: 1938.