Showing posts with label Shozo Michikawa. Show all posts
Showing posts with label Shozo Michikawa. Show all posts

24 October 2012

Higham Hall anagama, October 2012, firing continued

Shozo Michikawa pot, made and fired at Higham
.....a bit more detail about this firing now that I’ve been home 10 days already (I haven’t caught up with everything just accepted that some of it’s late and some forgotten and some just won’t get done)

Frustrating firing given that it failed to reach a good temperature. All those pots, all those miles, all that time. On the other hand lots of good company, lots of superb weather and lots learned.

We had a nice easy climb for 10 hours up to 900ºc using lots of the small wood (I mean very small wisps of wood bundled together, 1 - 3 ft long, 1/2 - 2 inches thick).
Then 4 hours of reduction keeping the temperature around 900º, building up ash in the chamber, using the damp wood.
The next 6 hours saw a slow rise of 100º up to 1100º. This would have been fine if the stokers didn’t have to endlessly rearrange the wood piles in an attempt to dry the wood around the kiln. It was tiring.
From hour 18 (4am) until hour 26 it hung around 1120º finally getting to 1150º at which point we started to feed in the soda through the fire box. We use Carol Nicols recipe of bicarb, soda ash and whiting.
Hour 32 and we’re at 1196º, the maximum achieved on the pyrometer.
Then 6 hours of consistent heavy reduction, continual feeding of wood which ignited before you could get it into the fire mouth. The fire had nothing substantial in the grate to maintain, let alone increase, the temperature. The ash pit was closed up as there was little ash to pre heat the incoming air. And the continual pyro watching, trying to get just a few more degrees.
By hour 39 at 1 am with the wind picking up and blowing onto the long side of the kiln we were actually losing heat so we started on the ton of big dry logs saved for the last stage of firing. Turned off the pyro, turned off the stress.
Now here’s the part which I don’t understand. Using the big logs gave a fire of white heat, minimal reduction, over a period of 4 hours, yet the pyro reading on the hour every hour, showed a decline in heat. And when we unpacked cone 10 was down in various parts of the kiln but most of the glazes were not matured - the exception being a pot of Shozo’s from the ash pit which somehow managed to be fabulous.

30 July 2010

For anyone interested here's the firing log for the anagama firing last week


Anagama Firing with Shozo Michikawa at Higham Hall


19th - 22nd July 2010


9.30am Monday. Light fire in ash pit, smokey,

1 10.30am flames being drawn up into kiln, place some wood into

fire box but continue stoking in ash pit.

2 11.30 some smoke from chimney, strong flames in fire mouth, cease

stoking in ash pit. Mix of pine and hardwood

3 12.30pm 490°C Pyrometer now working! Rake out ashes, reduce mouth

of ash pit to increase draft.

4 13.30pm 600℃ Raining

8 17.30 880℃ Still raining

9 18.30 970℃ Breeze blowing directly into the fire box

10 19.3 960°C Everyone present for the first reduction - lots of wood into the

kiln and then close the door over the fire mouth to decrease

oxygen in the kiln. Lots of smoke and dark red horns of flame

from the spy holes over the ware chamber.

11 20.30 990℃ Bit of a party going

13 22.30 1000°C Darkness falls, stoking mostly pine, some hardwood

23.55 1020℃

15 00.30 1005℃ Drop in temp after big stoke

16 1.30am 1040℃ Tuesday, first chimney flame visible.

17 2.30am 1050℃ Much quieter now

18 3.30 1065℃

19 4.30 1080℃

20 5.30 1090℃

22 7.30 1100℃

24 9.30 1120℃

30 15.30 1130℃

33 18.30 1120℃ Sushi interlude

34 19.30 1140℃

38 23.30 1140℃ Pizza. Stoking little and often

39 00.30 1160℃ Wednesday

41 02.30 1160℃ Deep roaring in body of kiln, good chimney flame

42 03.30 1160℃ Running low on wood, heavy stoking to maximize reduction

04.00 Last massive stoke

04.15 Final stoke, one piece of wood each, close dampers fully, clam

up ash pit.

43 04.30 End of firing, daylight.