|A quick peep into the firebox.|
After the fire box test that I mentioned last post, I demolished that one and also did major work on the kiln itself. I stripped out the chamber side wall lining bricks and replaced them, reconstructed the kiln floor, and built a new firebox...., much more sensible this time, but still with a step grate system, but much simpler and smaller than the one before.
With the new firebox and work done to the chamber, this is in most respects a new kiln, and it will take me a while to learn to get the best out of it.
|The firebox early in the firing.|
For the time being, this firebox uses two kiln shelves, a thick layer of ceramic fiber, and some insulating fire bricks as a roof, but I would like to do something different later, as I really do not trust the kiln shelves.
I glazed a kiln load of earthenware pots, most had been previously bisque fired, but I also included two 26 inch high pots that were raw glazed.
Loading took most of a day, and a further day was spent tidying around the kiln, finishing the fire box, and preparing wood.
|The warming fire made in a temporary add on firebox (note the cup of tea on top).|
The firing started last night, with a three and a half hour warming up firing of the kiln to 100 Celsius (212F), to make quite sure that the pots were dry. The fire was made in a little extension to the firebox that I made out of half a dozen bricks, and the heat from this was directed through the ash pit of the firebox. It was simple, and pleasurable, to fire, and nice to sit out in the dark with the happy crackle of the burning wood.
|If you look carefully you will see Nigella Stopit on the kiln roof. Laura is sorting wood. The kiln was at about 400 C (752F) when I took this photo. Almost no smoke visible.|
This morning I started the firing at 5.30am. The kiln was still a little warm from the firing the night before. This time I started the fire in the firebox itself. A very small fire to start with, and then a gentle climb. The step grate appears to be working well. There was absolutely no problem starting the kiln with this firebox, both for the warming fire, and the firing today, and the flame is bright and clean with no unwelcome smoke to overwhelm the stoker!
The step grate does take a bit of getting used to, although I am quickly getting to like it. Whilst navigating through the lower temperatures, there was always feeling that an unwise choice of wood or poor timing of stoking could have it galloping away. However, it is good to feel that there is a reserve of power available.
I must go and check progress. Laura has been stoking now from just above 500 degrees C (932F), and I guess we are around 675 (1247F) or so now.
Regarding wood firing.... it's good to be back!