Kiln Building In Ten Easy Steps

The kiln was built in spring 2005 with the help of fellow potter Mark Bristowe.
The chamber has a capacity of sixty-four cubic feet.

 
1
A concrete slab was cast on the floor to create a level surface, on top of which were placed insulation bricks. These were then covered with a layer of sand, then kiln shelves to ensure adequate insulation in the floor.
2
The fireboxes were built on top of the base using five hundred dense firebricks with a sand and china clay mortar
3
The chamber was entirely dry laid using five hundred High Temperature Insulation bricks.
4
A former made of timber was placed on top of the chamber walls to support the sprung arch.
5
Bricks were laid on the former using sand and china clay mortar.
6
A structure of steel tie-bars was constructed around the kiln to hold everything in position by local metal sculptor Steve Jones, the former was then removed from the arch.
7
Ceramic fibre insulation blanket was fixed to the chamber with chicken wire
8
The chamber was covered with a mixture of clay and vermiculite for additional insulation
9
John the Drums dry laid the chimney with common house bricks.
10
Job done!

 

The Kiln..Packing

The beginning of the pack.
The pots are packed onto tiers of fireclay shelves. Great care must be taken to ensure the pots don't touch and stacked in such a way to allow free path of the flame to all areas of the chamber.
All the pots are checked before packing and any glaze on the bottoms of the pots is sponged away to avoid molten glaze sticking the pots to the shelves.
The complete stack. Note the small brown spikes. These are pyrometric cones, compressed glaze spikes that each melt at different temperatures and visible during the firing.
The door is then bricked up. Several removable spyhole bricks are built into the door through which to view the pyrometric cones.
It takes Mark and me an entire day to pack the kiln and brick the door up ready for firing as the 63cu/ft capacity seems to gobble up hundreds of pots

Firing..

Small fires are lit in the fireboxes and gradually increased over a period of twenty-four hours of arduous stoking.
The kiln is fired with off cuts of wood from a bespoke kitchen makers and old pallets. John the Drums is a regular at firings with his chain saw ensuring timber of the right length is plentiful

The spyholes are removed at regular intervals during the firing to determine the temperature variation within the kiln.

The firebox in full operation, providing a great opportunity to toast one's kneecaps with every stoke!
The smoke from chimney acts as a reliable guide as to the atmosphere within the chamber and by controlling the amount of fuel and smoke, variations of tone within the glaze may be achieved.
Because of the lenghty firing and the intense heat, a whole team of potters and enthusiasts help. It is a frantic yet social occasion. Details of helpers can be seen under the link The Team. This picture shows Anthony Barclay stoking firebox one.
As the temperature increases, the flames from the spyholes become more dramatic!
The pyrometric cones within one area of the kiln starting to bend. Careful stoking must now be put in to play to ensure the cooler areas of the chamber are brought up to temperature without overfiring the hotter places.

Unpacking

The kiln is allowed to cool for two days bfore the door can be unbricked to reveal whether it has been a good firing or not.

The fired pots waiting to be unpacked.

Happy Me

Happy Boys

It was a good firing

 

The Wood-Firing Kiln

It takes about three weeks to make enough pots to fill the kiln. These are packed on tiers of fireclay shelves and then the door is bricked up.

A small fire is lit in the fireboxes with short lengths of softwood and gradually increased with a mixture of softwood and oak for a period of about twenty hours. I am fortunate to have a very supportive group of local potters who help with the firing.

The flame from the fireboxes dances amongst the pots and this, combined with the gases and smoke in the kiln chamber, provides the variation of tone within the glazes not achievable by any other method of firing.

When the fabric of the clay is thoroughly baked and the glazes matured (this happens at about 1100ºc, the chimney is capped and the kiln left to cool.

After two days the door is un-bricked to reveal its finished contents, a moment of triumph or sometimes disappointment, but the uncertainties associated with the process always a worthwhile challenge.

 

 
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