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Making Pots

Loading Pots

Firing Kiln

Unloading Pots

Report

Making Pots - October 2016

Bowls drying on racks - cheap plastic garden greenhouses which are ideal!

Mortaria bowls, "Celtic" iron age black burnished ware bowls. Raw glazed at stiff leather hard stage.

Large urns thrown in two pieces then joined with a tongued and grooved joint and thrown a bit more. Hopefully useful for bread bins - with turned wooden lids.

Experimental lidded jars, thrown in one piece with lid created by folding over the top and then pushing a flat stick into the side to make a step, after a night drying the lid is cut off and made to fit by a mixture of turning and throwing.

Cooking pots raw glazed.

Not casseroles because they don't have small side handles!

A set with lids all the same size, in case of accident - 4 lids for each 3 pots.

Pots drying in the front garden, stiffening up before turning and raw glazing.

Loading Pots November 2016

Sam, either very happy or he has just sat on something sharp!

Jill is a more sensible height than Bill to stand inside the kiln!

Jill and Steve helping to load

The back section of the kiln almost loaded.

Bill forgot his camera on the other days' of loading, but some more images may appear.

Firing Kiln - 19th November 2016

The preheat started at 9pm Friday evening, 3 hours earlier than recent firings.

Thanks Diane for the suggestion to start and thus finish earlier and for the loan of the alarm clock, which couldn't be slept through.

The night was blustery.

Kate V's logs kept the fire going overnight - restoked every hour during an interupted sleep in the car!

This image shows the logs slowly burning to embers.

A new dawn! Two new logs thrown in and beginning to burn.

At dawn the birds arrived for a quick look at what was going on.

Sunrise, shame the kiln got in the way of that!

A few moments later.

A beautiful calm start to the day, which was not to last!

1000C at 11.15am - well ahead of schedule.

Steve beginning his shift of stoking the fireboxes, while Bill goes off to pick up some more pallet wood.

Not much change in temperature during Steve's session!!!!

Although 1000 C to 1100C is always a slower rise time.

Flames can be seen through the cracks in the tunnel leading to the bottom of the chimney.

These show how much unburnt gas is leaving the kiln before giving up its energy.

Towards the end of the firing the flames sometimes can be see coming out of the top of the chimney.

Steve in action, mid afternoon. Artistic photography by Bill.

Mid afternoon, the flames sometimes come out of the firebox doors, as the newly introduced wood gives off vapours which rapidly expand and create positive pressure in the firebox and kiln chamber.

When the chimney is pulling properly there is a negative pressive in the kiln as the hot air rushes up the chimney and air is sucked into the firebox.

Dusk and the floodlights are on.

8pm and the stoking is going well

1230C at 8pm. This temperature was much easier to reach than usual. The calibration of the cheap digital thermometer is out and so this is actually nearer 1270C, as can be seen from the Cone 8 beginning to bend over, as seen through the spyhole..

Richard arrived for the evening shift, bringing very welcome fish and chips. Here he is in action - stoking away.

With the rain starting to get torrential, it was brilliant to have finshed the "soaking" at 9pm - after an hour or so at that high temperature the glazes should all be mature and with oxidised burning the smoky residues should have burnt away and left the glazes sparkly!.

So then the doors were all opened and the kiln crash cooled down to 1100C in about half an hour. That fast cooling stops large crystals forming in the glazes, so they do not turn milky.

Then the bottoms of the firedoors were blocked up and the stokers headed home.

There were some gaps between the bricks in the door. Bill should have tried harder and perhaps used ceramic fibre between them?

The flames find the gaps whenever the pressure in the kiln rises.

More ceramic fibre insulation had been added as cladding around the kiln, filling in the gaps that had not previously been covered and repairing an area that had collapsed when the chicken wiring had rusted out through the extreme heat coming from the firebox. That fibre was wrapped in aluminium foil and covered wih the chicken wire netting, then strapped to the kiln.

This is a graph of the firing schedule.

Unloading Pots - November 2016

The first sneak look into the fired chamber!

Heavy reduction, nice shine.

View of a pair of pyrometric cones, 8 & 9, right at the top - well melted over - so a good 1270C at least.

After the brick door is taken away the pots are revealed.

What is this concept about being vertical?!

The higher half is more reduced and higher temperature.

The cones seen through the spy hole are just about text book bent.

At the bottom on the right it is too cold. So the glazes have not quite matured

Bill with the second pot to be taken out (the first was a beaker for him to drink his coffee from!)

The back section of the chamber - after the front section had been removed.

Slightly more verticality!

The back bottom section.

Nice and warm - the cones in the middle first shelf up are well bent.

Peter Woodward's assemblage of mostly anciently inspired pieces.

Belinda's Canada Goose.

After a bit of touching up with heretical black bake on glaze.

Anna's experiments with black iron oxide over white glaze.

The oxide promotes melting, so the design has run, turning the hens into dinosaurs!

Hilary's hand built cylinder, with a beautifully ash reaction with the light oatmeal glaze.

Caroline's experiments with clay slip and ash glazes.

Caroline's craggy finishes, large pieces of broken pottery pushed into soft pot. Covered with slip glaze, which resists the attack of the ash.

Caroline's hottest fired piece.

Hilary's twisted vase, another great ash event!

Libby's mugs, with bands of glazes running where very high fired.

A couple of Doug's bowls

A pair of Richard's bowls

Richard's large urn

Sam's vase and beakers.

Awarded certificate for lightest pots in kiln.

Sam's bowls.

(Photo by the artist! Spot the Graphic Designer!)

Bill's mortaria after cleaning up

A pair of Bill's larger jugs

Bill's "Celtic" bowls, inspired by black burnished ware

Close up of BBW bowl, showing lattice decoration which was scratched into the leather hard clay.

Bill's "Maggot" bowls

Close up showing "maggot" decoration - inspired by Neolithic ware that a Victorian antiquarian said looks like a maggot has been pushed into the damp clay. It is actually cord with another cord wrapped around it in a tight spiral.

These two show the difference in the amount of reduction in the chamber - the lower one was at the bottom right front cold spot, away from the flames.

Bill's beakers

Close up of decoration, impressed with the tangs of a wood comb.

Bill's storage jar, or it could be a cooking pot!

Decorated with rope impressions.

Bill's jars, experiments in making vessels with small lids.

Close up of Bill's jar with decoration inspired by Iron Age Glastonbury Ware.

Bill's large jug, thrown in two halves - one upside down - then joined and thrown a bit more to create the neck and throat.

Bill's attempts at jars or cooking pots. 9 vessels, 12 lids all the same diameter! Bill must practice lid making a bit more!

Report and Conclusions

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A great firing!

The highest digital reading was 1250C, which was as high as it has ever been fired, although new thermocouples in new porcelain sheaths were being used and they were in a higher position at the top (actually welded to the roof arch!) and a lower position at the bottom.

The temperature did not drop too rapidly each time it was stoked, when following a ritualised constant regular schedule of stoking it worked well. Waiting for the flames to stop emerging from the top of the front of the kiln, then stoking, rather than over stoking or letting the fireboxes become empty of glowing embers. The end being hit by the wind had fired better than the other end, which was suffering from the flames and heat being blown back out of the door when the wind increased occassionally.

In the face of Storm Angus, the loading and stoking crew did well. They are beginning to get into the swing of firing now, the stoking was more regular and effective (except when Steve was left alone and the temperature remained the same for a while!). Good supply of dry wood, Kate's logs were great for the first 1000 degrees. Pallets and roof battens good for finishing off.

Probably the easiest effort to reach the highest temperature quickly and keeping it there. The repaired and improved ceramic fibre insulation must have helped. Together with a bit of a breeze. The rain didn't seem to make much difference (except to the morale of the stokers).

Thanks to Steve for not making a motivational speech this time round!

Looking forward to the next firing - Bill had quite a few of his pots left over, so perhaps the next firing can be sooner than usual, maybe March 2017.

Comments are very welcome - email Bill Crumbleholme

Thanks to :-

Crumbleholme Builders for the timber offcuts and roof batten.

Winterborne Abbas Pallet man for broken pallets.

Kate V for her felled nicely seasoned logs.

www.onlineshells.co.uk/natural-cockle-shells-p-3855.html

The Landlord for support and encouragement.

Pottery Class members and other potters for help filling the kiln and then firing and unloading it, especially Steve, Peter, Sharon and Richard.