The firing day started calm, but gradually the wind picked up and the drizzle increased. The wind helped to burn the fuel more efficiently and this was the fastest firing yet - all over by 8pm.
This is a view of the cones through the spyhole.
The cones are the diagonal uprights, which melt and bend over at specific temperatures (or when heated enough over a longer period). They show when the glazes should be mature.
Here they are still upright - this was at about midday, after an all night gentle preheat - a couple of logs of elm every hour and a half or so to maintain about 100C to dry out the pots and the bricks of the kiln.
From 6am the stoking was increased to bring up the temperature to 1000C by midday, when a period of reduction was started by removing the passive dampers in the chimney, that cut down the updraught.
A flame is coming out of the cone spyhole, showing that reduction is happening, as a positive pressure builds up inside the kiln chamber, filled with smoke which draws out the oxygen from the clay and glazes.
The passive damper hole was used to cook some pizza, by the ever-hungry Laurence. It worked very well, as did the baked potatoes in the evening!
The fuel used was mainly elm logs, whole to start with, then split into halves and quarters. Some pallet slats and other surplus timber was also used towards the end.
It was found that if the slightly damp pieces were placed in the bottom of the firebox, they would dry out and start to burn. Then they were put into the top of the fireboxes, where they immediately ignited, without causing the usual drop in temperature, suffered as the initial heating and burning took some energy from the fire. So reaching 1250C was not too much of a struggle and keeping it soaking for a couple of hours was not too difficult.
The digital thermometer behaved well, showing the rise in temperature, with two thermocouples placed near the top and bottom of the chamber, this firing showed the bottom being hotter than previous firings. However the actual readings are not in calibration as they showed 1170C when the cones when over at 1250C.
The firing was the easiest so far, in terms of burning and stoking, but the weather was very wet by the evening, with mud all round the kiln site and local roads flooded. The stokers are likely to strike if they do not get a better shelter in time for the next firing!