Joseph Herbert on fri 16 mar 01
Jim V wants to know more about cullet in glazes. The books:
“Turners and Burners: The folk potters of North Carolina”, Charles G. Zug
III, University of North Carolina Press, 1986 devotes a chapter to glaze
formulation that mostly includes glass as a major component.
“Raised in Clay: The Southern Pottery Tradition,” Nancy Sweezy, University
of North Carolina Press, 1984, 1994. describes the kilns, ware, and glazes
of many potteries throughout the southern United States.
Provide insight into the use and development of glass based glazes. Both
are interesting reads on both a human and technical level. One interesting
thing is the practice (in times long past) of selling the ware for 10 or 25
cents per gallon of capacity. A five gallon stoneware churn would then sell
for 50 cents or $1.25. Pretty hard to support that North Dallas residence
at that rate.
The descriptions give rough percentages of wood ash to clay to glass powder.
As David Hendly indicated, this is a variable proposition that requires
testing and close attention. It may be revealing that in later times, when
processed materials (Glaze Chemicals) became available, to some of these
potters, they chose to replace the glass component of their glazes with
whiting and feldspar. This was probably because it was a lot less work and
the composition of the purchased materials was more consistent than the
glass powder.
Joseph Herbert
| |
|
