This kiln proved quite tricky to fire in terms of getting the temperature up to 1285 degrees C but according to the pyrometer, I finally got there after 10.5 hours. At various points the temperature would stick and I had to make minute adjustments to the burner position and damper to get it rising again. No doubt the firing may have been alot quicker had I been able to use HTI bricks throughout. Cone 10 didn't quite drop but 9 was well over on the bottom shelf, where I think it was slightly cooler.
After the kiln reached 900 degrees C I started stoking occasionally with 2 or 3 pieces of pine kindling and each time this would cause a temperature drop of around 30 degrees. Over 1200 degrees this became quite exciting as large flames would shoot back at me out of the side stoke hole as the wood combusted instantly. I would like to have used alot more wood but it was so difficult to get the temperature up that I had to hold back on creating more reduction. At the end of the firing, the gas was turned off and six or seven small pieces of wood were pushed into the burner port and side stoke hole in an attempt to achieve more reduction during cooling. I felt this was necessary as the walls of the kiln and the roof are far from air-tight, and sure enough, the following day there was nothing left of the wood, barely any ashes at all.
A couple of shots of the kiln as it was dismantled:
|Kiln built on wooden pallet, burner port on right.|
|Kiln with spy hole and stoke hole for wood (right) on facing wall|
I think the addition of wood helped in creating intense bursts of reduction throughout most of the kiln, although it's hard to know exactly how it affected the glazes, as many of the pots already had raw ash added to them before the firing. Pots placed near the exit flu were more oxidised (example in the second photo). As usual, I was testing quite a few new glazes so the results were very mixed .. here are some of the pieces I felt turned out okay:
|vase, 2 ins tall|
|vase, 3 ins tall|
|vase, 9 ins tall (re-fire from wood kiln)|
|vase, 5 ins tall|
|tea caddy, 4 ins tall|
|vase, 3 ins tall|
|vase 3.5 ins tall|
|Vase, 2.5 ins tall|
|whisky cup, approx 3 ins tall (re-fire from wood kiln)|
|whisky cup, underside|
The little bowl on the left was given a coating of groggy black clay (when leather hard) and this has added an extra dimension to the glaze in terms of texture and colour. Can't wait to try this one on a larger pot!
Thanks for reading.