Anagama Complete. Sutema constructed, front and rear checkers cut and positioned and Chimney rebuilt; I have become drawn to building again loving the simplicity but focused upon the accuracy of hand to spread muck, level bricks and construct. This turns my head off, with the job demanding my full attention…hours pass. I wonder if I’m so attracted to this activity because I played with Lego as a child?
The alterations did not go smoothly, much due to a lack of time and bricks (I ended up rummaging old piles of discarded kiln bricks and needed to cut many Heavy bricks with my Angle Cutter and HTI’s with hand saw, to square them up) I studied your Plans and amendments to my Sutema designs. Our telephone conversation was the most important guide, as the best plans/designs are always open to interpretation and dependant upon one’s experience and therefore I gained much from our discussion obtaining details and corrections to some of my Kiln Knowledge.
I built the Sutema in the same manner as the kiln; as an added extension. The Sutema is divided by 2 walls. The dividing wall from Pot chamber has two 6’’x 2.5’’ flue holes, jpeg-8, at the base. These flue sizes will determine the entrée air inlets, ‘what comes in must go out’ (Fred Olson, 1983).
My Question here is: do these Flue holes need to be larger? My feeling is they do need to be larger, if so I will take out the 2 small side supporting Bricks and allow the central brick to support the 1st Sutema Wall. This will then make the two Flue Holes 6” x 3.5”.
The ‘Hachi-no-su’, second wall was a lot more complicated to decide upon its structure. I first built a simple 6 chequer exit but felt this was too open. On close inspection of your drawing I changed this to copy your design structure. This interpreted resulted in an 8 chequer exit, jpeg-7.
I’m not sure if my interpretations of your drawings are correct? My reasoning for using an 8 chequer wall was in considering that the gases entering the Sutema would be held back with a more complicated design and this would keep the flame back in the Pot chamber.
The inner Sutema dimensions are 33 cm in Length and with the Endou length of also 33cm, before entering into the Chimney base. The wall and Arch thickness is 9 ‘’.
The inner wall is made from good Super Heavy brick and outer wall built from left over odd sized Super Heavy bricks (I’m at the end of my original fading stock of Bricks).
The mortar used was a slackened down general plastic Clay and applied with a minimal layer aiming to place and wedge brick upon brick.
The Arch was made by constructing a wooden former, jpeg-5. Then I built a Bonded Arch using HTI Bricks, jpeg-6. I have used HTI’s in both of my small Anagama Kiln Arches because they are very light and so, will not push out the vertical side walls of the Kiln from the angle of their thrust, jpeg-6. The Arch was insulated with left over HTI’s and 50/50 ball clay and sharp sand, jpeg-12, to make an over-all thickness of 9”.
From my talk with Svend in April I was drawn back to his idea of placing air inlets into the sutema. I have done this and these are equally spaced in the Sutema arch. The air inlets will act as passive dampers to slow the rate of flow. In future firings I will experiment with these and, as discussed with Svend, they may possibly aid the combustion of waste gases and so effect the amount of reduction? jpeg-9. (I beleive this is a discussion for a futuere date)
In one of my previous correspondents I had calculated that according to Fred Olson (Principle of Kiln design, 1983) I needed a larger Chimney base cross section. So I have changed this from 9’’x 13’’=117 cubic inches, to 13’’x 13’’= 169, jpeg-4. This dimension stays the same for 15’’ vertical then tapers over another 15’’ vertical to a final 9’’x9’’ Chimney section, jpeg-11. I have also built in a larger Passive Damper at the base of the Chimney which can be blocked off if needed and following our discussion I have put in a main Damper in the Chimney.
Although I have built additional devices into Chiisana Kama I am reluctant to use the Sutema Passive Dampers and Chimney Damper on the first firing. Instead I will fire the Kiln purely using the addition of the Sutema. As agreed and talked about in our telephone conversation too many devices altered and changed when firing an Anagama can be confusing to the kilns over-all performance; making too many changes could make the kiln erratic and stop the Kiln finding its natural pattern. Future Firings will experiment with the additional Dampers.
So with alterations done wood will arrive this week and sawing, stacking begins for a much awaited 2nd Fire.
I am really honoured that you would like to visit my Anagama Kiln. And I would, also, very much like to meet your friend James Hazelwood. James has previously contacted me regarding my reference in the forthcoming book on ‘British Studio Pottery Marks’. I much appreciate the difficulties and determination James has undertaken with updating this catalogue and would like to meet and thank him in person, he sounds like a good man.
Unfortunately there is under lying news…You asked to visit ‘soon’ and this I would urge you to do soon. Weston Quarry is run by a Civic Society and recently new members have been voted in. This new Committee is less interested in the Arts and there is talk that the Artist’s Workshops will be closed for refurbishment or a change of purpose maybe made on the Workshop/Studios. So me and other Artists maybe given notice to leave. At present I am facing, in the worst scenario, Firing Chiisana Kama only once. My time over the last 4 weeks has been much distracted by this news and I have had to work on ideas to try and persuade this Committee that an Anagama kiln is a rare feature and could be used as a positive community project and attraction for Weston Quarry. There is a meeting this Thursday that starts the first of many new Changes. I will have to present my proposals soon.
So I am making work and need to stay motivated. Recently I have been attracted to the idea of ‘Landscape’. I am making large Clay slabs, similar to my older but smaller ‘Table’ forms. My aim is that this form will record the flames flash and will capture an accumulation of fly ash achieving a Landscape scene that reflects the woodlands that I observe and study when walking. This Work has been developing slowly over the last 5 months. Bringing these ideas together with Chiisana Kama’s potential will be challenging but a needed vision (in these troubled times) for a positive 2nd Firing.
Look forward to hearing from you and Thanks again.
I like your “chiisana Kama” with ‘Sutema’ very much and it looks much better. The proportion of Sutema (the front wall flues and the second wall honeycomb “Hachi-no-su”) seems just about right to me. I believe (also hope) it would work better and you will see when you fire it soon.
I also agree with your decision on the passive dampers completely. If you can perform wood-firing without (not too much) adjusting dampers, it means your kiln design is good and working fine.
My ‘Moby’ has no chimney dampers at all. Yet, strangely enough, my latest ‘Moby’ has two air inlets with movable bricks around the same position as your “chiisana Kama” has. I have no intention of using them unless I become desperate. Almost all of my anagama didn’t have proper passive dampers as I mainly relied on natural reductions, so I won’t be able to give any good suggestion about passive dampers and forced reduction to you. You should ask Svend about these questions.
Sim, I really appreciate your information of the “Chiisana Kama” kiln project, moreover your generous contribution will be beneficial to all wood-fire enthusiasts.
Looking forward to meeting you some time very soon. (Gas)