Mid winter and mid summer firings

We are lucky in the UK that the weather is fairly temperate and so the firing season is pretty much all year round. That has not stopped us having to fire in some fairly extreme weather (usually being forced to by a neglected deadline suddenly sneaking up on us…) The first time was in minus 2 at the end of January, and then in July in the 34 degree heat. The firings were near-opposites in every way, including in results.

In January, Hamish Jackson was up in Stoke to give a masterclass at Clay College. We had been speaking and he was committed to an exhibition at NCECA showing high alumina soda fired work, but he had not yet built a soda kiln since returning to the UK from the states. Reading Hamish’s blog has been so helpful in navigating the surfaces I wanted to explore, and so the opportunity to possibly fire with him was a full circle moment, and indeed a very special one. I suggested that he come up early and we fire the soda kiln at Vulcan Works.

That would be firing 3 of that kiln. In the second firing, the bottom was a bit under-fired (cone 7). We had a chat and decided to block up some of the exit ports at the back of the kiln at the top and middle, to try to encourage the flame to move through the bottom of the pack. We were, however, a bit too pluggy-blocky….

_{pluggy-blocky…. We may have gotten a bit carried away blocking up the back of the kiln}

The kiln stalled in the 1100s, and it was a similar experience to firing with wet wood in a wood kiln (which I have had the displeasure of having to do on a single occasion and would not recommend it to anyone) – the combustion just could not release enough energy for the kiln to climb, everything was bunged up and choked. We sat there for hours and hours, the whole firing taking 6 hours more than normal and ending at 3am in the minus fours – at least, by then, the kiln was keeping us warm.

Speaking of keeping warm, the firing itself was not too bad, but rolling wadding balls, packing the kiln, and placing all the kiln shelves in that weather was a little bit challenging and definitely made us feel more tired by the time the firing came round.

_{kiln packed}

To get out of the 1100s we ended up turning off the middle burner, and firing just from the front with loads of fuel at high pressure. We also added four courses of bricks to the chimney to try to draw in more secondary air. This forced the issue and got us to cone 8 front and back so we could start soda introduction, and we also put the middle burner back on low at that point. The over fueling during that period produced some extremely dramatic carbon trapping(!) In amongst it all though, were also some amazing deep reds, very warm flame painted marks, and great satin soda glass.

This bowl of Hamish’s was a particularly stunning example of the complexity of the soda fired surface

I learnt a lot in that firing, and despite the stall, the bottom was much more even. The firing also saw the first real world implmentation of the soda pew-pew…

_{Em and Hamish delivering soda with some heavy back pressure}

With the kiln being more even in that firing, removing just a couple of the plugs for firing four meant that now the kiln reliably fires as evenly as you can expect a cross draught kiln to fire (now, the biggest difference is right to left rather than top to bottom).

Firing 5 was the summer firing. The write up of the firing will wait until another day, but the results from that one could not be more different. Subtle, flame painted marks, with reds, pinks and oranges, and very little carbon trapping. You can see some of those results on my post about cordierite bodies.

Two weather extremes, two aesthetic extremes. I love how the same clays can sing to a different tune depending on how the kiln is fired. It is important to never stick too closely to a set menu, or else you close the door to the near-endless possibilities that flame painting can open up.