This category includes a variety of methods, both manual and mechanized.
They all require the starting mixture to have a plastic consistency, which is generally
achieved with 15% to 25% water. Manual methods generally make use of clay at
the upper end of the range because it provides a material that is more easily formed;
however, this is accompanied by greater shrinkage in drying. Mechanized methods generally
employ a mixture with lower water content so that the starting clay is stiffer