The firing shrinkage of a clay is usually about the same as the drying shrinkage. Total shrinkage will usually be about 8-12%. The next stage that happens during the firing process is vitrification. This is the hardening, tightening and finally the partial glassification of the clay. Vitrification results from fusions or melting of the various components of the clay.
Middlesboro (local /ËmÉªdÉlzbÉrÉ/) is a home rule-class city in Bell County, Kentucky, United States. The population was 10,334 at the 2010 U.S. census, while its micropolitan area had a population of 69,060. It is located 1 mile west of the Cumberland Gap and is the largest city in southeastern Kentucky. It is located entirely between Pine Mountain and the Cumberland Mountains in the Middlesboro Basin, which geologists believe to be an enormous meteor crater (one of three known astroblemes in the state).
Pennsboro is a city in Ritchie County, West Virginia, United States. The population was 1,171 at the 2010 census. The city is located at the junction of U.S. Route 50 and West Virginia Route 74; the North Bend Rail Trail also passes through the city. The town was platted about 1820 by Charles Penn, and named for him.