On 30th July we set two large and two small empty pots in the melting chamber and undertook a half-day firing, using three-feet lengths of wood, to test the grate. Although there is a photo of wood being weighed, this time we did not record the amount of wood used.

We started at 2.15pm, and by 6.15pm the temperature had reached 1153°C and was still climbing, so to avoid possible damage to the furnace we allowed the fire to die down.

This firing showed that the grate worked as intended, with the extra air pulled in under it providing enough oxygen to burn the charcoal to ash and giving us the ability to reach higher temperatures than on previous firings without the grate.

Although this firing did not appear to damage the firebars, it is worth noting that after the two weeks of Firing Four (see this page), the two bars closest to the centre of the furnace were all but destroyed. Although we will continue to use stainless steel for the next firing or two, we will eventually replace the metal firebars with fired ceramic tubes of the same type as are now supporting the pot shelves.