The Making of the Glencairn Methuselah Window: Page 11
MODELLING CLAY BACKING
Put material in about 10 o’clock - within a few minutes raised the Rheostat to 8 points there it is to remain until 1660°F is reached
Reached 1660°F at 12:15 P.M.
Front crucible removed lid removed
Material poured out at 12:15 into an iron pan with a little water in it. Smashed in an iron pot, but this should not be as the iron coming off would make the color a little blackish
The best way is to smash up material in porcelain mortar with porcelain pestle
I added to this for grinding 262 grammes of water for grinding in the pebble mill