can I just correctone small factual error in Adam's otherwise excellent post about pots, as someone inbolved in pot buying and use.
You do not "allow the furnace to cool, remove the old pot and heat it up again"!
A furnace has to be cooled slowly so as not to damage the refractories ( bricks, etc), so it would take three weeks to cool down and three weeks to heat up!
So you do a 24 hour pot set, by removing the bricked up front of the furnace taking out the old hot pot ( on a gun carriage or shielded fork lift truck) and replace a pre heated new pot and the bricking up again.
About 3 to 5 hours for a team of 5 guys who loose about 1/2 a stone (7lbs in weight0 through sweat and exercise.
At Nazeing Glass we got up to 18 furnaces ( single for of 750kgs a day). We now have four and two 100kg studio pots, but not all are in use!