Wood firing on Friday 25^th June

Firstly, apologies for the delay in the write up of the wood firing last month. You’ll have to make do with my amateur scribbling this time, rather than the superb writing of Gareth for the man be most busy with making work for his forthcoming exhibition.

I (Sam) was mainly present after 5pm, so missed out on much of the activities throughout the day, but here is a summary of what occurred:

We packed Bertha (for that is her name) on Thursday 24th, which took much longer than we had planned (our 5pm finish soon became 9pm), but this would have been much later if it wasn’t for the help of various kiln club members, so many thanks to all! We decided to put in three spy holes (top, middle and bottom) as from previous experience the kiln fires unevenly with the bottom being hotter than the top.

The Friday began with Gareth rising at a ridiculously early hour to begin the firing at 4.35am, from whence he gently nursed the fire at a rate of 80-100c per hour.

He was later joined by new member Jay and at the positively late hour of 8am by me. The beginning of the firing is always a time for gentle stoking intermixed with conversation and lots of cups of tea!

Throughout the morning other kiln clubbers arrived and all took turns in stoking the fire, and it continued to climb at a steady rate.

After Gareth and Sam’s previous mammoth long firing we had learnt from wood firing guru Graham that when there is a build up of ash in the fire box this has to be raked out. Although it seems a contradiction to remove heat from the fire box, Bertha needs lots of air in order for the temperature to climb. We’re still learning as to how much ash to rake and how often, so this will no doubt change with each firing. One of the challenges and delights of wood firing is that no two firings are the same and so it’s important that we learn to respond to the kiln and adapt to each firings quirks and differences.

To this end the first raking of ash was at 3.30pm and throughout the rest of the firing, thanks to the stirling efforts of Rachel and Richard, and this certainly seemed to work. By the end of the firing Rachel had a nice dusting of ash all over, so I’m sure the bath water was a nice colour of grey!

At 5pm Gareth had to leave the firing for a couple of hours, due to country dancing and cake eating commitments, so I came to ‘oversee’ the firing. I’m by no means a wood firing expert, so hoped that there would be no disasters over the next couple of hours. Richard was well in control of stoking the kiln and all seemed well with the temperature gently climbing.

At 5.45pm the temperature on the pyro was 1165c, but thought I should have a peek inside the kiln to check what was really going on, and am really pleased I did! At the bottom of the kiln cone 5 (1200c) was fully bent, in the middle the cone was halfway over and at the top it was just starting to bend. A reminder of the importance of looking inside the kiln to see what is really going on, rather than relying on reading the pyro and presuming that it’s reading correctly.

After this initial bit of excitement the challenge of wood firing became apparent, in that temperature climb was slow and erratic. We tried different kinds of stoking, playing round with the tile at the front of the stoke hole, raking out the ash etc. Another reminder that wood firing is not text book firing and one has to adapt the situation and learn to look and listen to what the kiln is telling you. Without the guidance of Gareth I began to question how the firing was going, as the kiln was most definitely hotter at the bottom, so I felt we needed to try to even out the temperature rather than just go for temperature climb. In order to aid this we played around with the damper and passive dampers, and although that slowed down the temp climb it did have an impact on overall evenness within the kiln.

With Richards and Rachel’s ash raking and stoking, the kiln responded and thankfully Gareth returned. Sarah had the genius idea of bringing potatoes which went into the bins of ash, and gently cooked for an hour after which the most delicious jacket potatoes and beans were consumed.

As time progressed and the temperature was most certainly rising, a discussion was had as to whether to keep on stoking in order to reach temperature, or to slow things down and concentrate at introducing ash to the work which would entail a couple more hours of work. As the kiln was firing unevenly the unilateral decision was made to go for temperature climb.

With a temperature of 1300c on the pyro and cone 10 (1300) looking like chewing gum at the middle and bottom, and cone 9 (1280) just starting to bend at the top we ended the firing at 8.51pm.

The following week we unpacked the kiln and as always there were surprises and moments of beauty and joy.

Make a range of work all different sizes, often there are small gaps throughout which can be filled with work.

Don’t expect all your work to go in, we try to fit in at least three pieces per person.

Remember to leave a good gap between the bottom of your glaze and the base of your work, approx 2cm.

There is a lot of time and effort that goes into the wood firing even before the day of the firing, so if you want to have work in the kiln you must participate in the preparation process. We will endeavour to make this on a weekend and give plenty of notice in advance.

Happy potting and let’s make fire!