Tuesday: I loaded the wood fired kiln. It was a hot, and the day reached 27 degrees C at some point, which is not bad for Autumn! I loaded as much as I could first thing in the morning, then did the rest after 5 in the evening, finishing by torch light.
|Smaug, the cat, by night!|
|Bowl from the electric kiln.|
I lit a small fire last thing in the day to pre-warm the kiln, then went to bed.
Thursday: A bit of a wakeful night had me finally out of bed about half past four. It rained heavily at times in the night, and still was spattering against the windows as I got showered and dressed, had a good cup of tea, followed by some coffee for good measure, then put on some extra warm layers of clothing before flinging open the back door and walking bravely into the night.
It was black outside, and a stiff Southerly flung splatters of wet stuff into my face. My stupid smartphone app claimed that it was 9 degrees, but it felt like 4 or 5 at most ... I don't think that the weather man had bothered to venture outside!
I lit a fire at 5.26am, and settled into kiln watching, feeding a little fire in the ash pit with sticks and thin pieces of split wood. My feet were getting cold. I listened to trucks snoring past on the Main Road, their tyres making fat frying sounds on the wet asphalt. I like firing in the rain. I have a blue tarpaulin stretched out over ropes behind the kiln to give extra shelter from the weather. It feels like camping.
Soon the inside of the kiln was a snug 100 degrees, and there was a merry crackle and snap from the fire and the smell of wood smoke and warming brick.
Thanks to the fire box and ash pit doors, very little heat escaped. Brrr cold feet!
Laura joined me out at the kiln at 6.30am when the kiln temperature was showing 150 degrees and took over stoking for a couple of hours. I brought out hot drinks and some breakfast.
My turn again when the kiln was just over 300 degrees. It is an interesting part of wood firing that every firing feels different, the weather, the wood, the way that the pots have been packed in the kiln, all have an effect, there are so many variables! This firing felt more demanding than the previous one. More thought and care was required to make the temperature rise, but rise it did!
At 9.35am Laura was back at the helm with the kiln nearing 600 degrees. An hour later, with the kiln at 750 I took over, and kept going until the end of the firing.
I put the kiln reduction from about 800 degrees, and kept the fire fairly smoky until 1050 was reached, then I established a rhythm of -
stoke - watch for chimney smoke, wait - - for - - it - - to - - clear - pause for temperature to rise - stoke...
By fine tuning the length of the pause, I could fire reducing to neutral atmosphere, or reducing to oxidizing.
|A reducing atmosphere is always hungry for oxygen, expect flames from spy holes when inspection bricks are removed!|
1200 was reached a whisker after 1pm. I slowed the rise of the kiln and managed to keep the kiln over 1200 and slowly advancing for the next 2 hours. My pyrometer reads about 60 degrees low, so 1200 indicated is a reminder that it is almost time to start checking cones.
|A pack of cones, from cone 8 to 10. I love the trails of incandescent gas that loop and roll through the chamber of the kiln.|
At 1.30pm cone 9 was well bent in the hot top part of the kiln, and cone 8 was bending in the middle of the kiln.
|Cone 8 bending... can you see it? It takes practice to see the cones in a hot kiln and it is important to wear welding goggles or similar eye protection.|
At 2.45pm cone 10 was down at the top of the kiln, and cone 10 was half down in the middle of the kiln.
3.15pm last stoke of the kiln. Cone 11 half down in the hot top. Whilst I was cone watching, someone had discovered that a kiln chimney and the kiln shed roof is nice and warm whilst the kiln is being fired.....
|Smaug, enjoying warmth worthy of a dragon!|
At 3.25pm ten hours after lighting the kiln, cone 11 was down at the top, cone 10 in the middle, and cone 9 in the lower part of the kiln.
3.45pm the kiln was all clammed up and the temperature falling quickly.
Smaug was delighted by the kiln, and spent the whole afternoon lounging around on the warm iron roof.
It was a very good firing. I was delighted to have been able to keep the kiln above an indicated 1200 for 2 hours (about 1260 C corrected). I do think that the pots benefit from spending time at that temperature.
|Sunday morning, a first look into the kiln.|
I was able to open the kiln Sunday morning. First glance in the dim kiln showed pots that looked a bit brown and drab, but unloading revealed some rather splendid things had happened after all!
|Fascinating copper blue over copper red! Strange and extraordinary... I must do more of this!|
The saturated iron red was superb in this firing, the kiln must be cooling slowly enough when below 1000 degrees for iron crystals to grow in a lovely way. The runny ash type glaze makes exciting rivulets over it, that are green in colour.
|Van Guilder Ash over Deboos Iron Red|
|Van Guilder Ash over Malcolm Shino|
Regarding the "fake ash", unlike the news, there is nothing "fake" about this glaze, it does have 15 percent of unwashed wood ash in it, but it also has 31 percent Whiting (calcium carbonate) as well, so whiting outranks the ash to some extent! Whiting can give very ash-like effects in glazes, but is easier to prepare and use than wood ash. Using ash and whiting together like this can give a more consistent result than pure wood ash alone, but it is still lively and interesting!
I like to tuck a special pot on a small shelf over the fire box of the kiln. Anticipating some runs from this glaze I, fortunately, put some offcuts of insulating firebrick under the pot.
The pot has a rutile glaze over a dark tenmoku glaze. This combination usually gives a complex blue colour, but this time it is almost black with glittering small crystals and pale feathery streaks. Wonderful!
|A rather spectacular heavy bowl with copper red inside, and rutile over tenmoku outside.|
*Van Gilder Ash (I have fired this successfully from Cone 8-10). Very runny but behaves quite well at cone 8 - 9. You will find this recipe in John Britt's excellent Cone 10 glaze book, "The Complete Guide to High-Fire Glazes".
Wood Ash 15
Potash Feldspar 5
Ball Clay 24
Red Iron Oxide 0.75
Cobalt Carbonate 0.5
*DeBoos 154 (I have fired this successfully from Cone 9-11). This recipe is in Glazes for Australian Potters by J. DeBoos.
Soda Feldspar 50
Bone Ash 10.5
Ball Clay 7
Red Iron Oxide 11 (gives iron red. 3 parts gives olive green).
More photos of pots from this firing will appear over the next few days. As you will have seen, Smaug is enjoying life at the pottery. He took a few days to get over the loss of his twin brother, Brian, but he has his sense of humour back again now and is good company.