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Making Pots

Loading Pots

Firing Kiln

Unloading Pots

Report

Making Pots - May - June 2016

Bill made many of the pots while demonstrating during the Upwey Potters annual exhibition as part of the Dorset Art Weeks.

"Mortaria" just thrown and turned and then raw glazed internally with light oatmeal glaze.

More of the same and some bowls without the lip.

Bowls inspired by Black Burnished Ware, with latice decoration.

Bowls inspired by Neolithic "Maggot Bowls", decorated with whipped cord vertical lines. These have almost round bases, like their inspiration.

Loading Pots 2016

Back of kiln chamber loaded

Front of kiln almost loaded.

Many of the pots were made by Bill's class students and other local potters.

The front loaded and ready to brick up.

Steve, the axeman, after a day chopping wood and brushing kiln shelves!

Firing Kiln - 17th June 2016

Late morning, Bill doing a David Attenborough impersonation!

After a night of gentle pre-heating, stoking every hour, with thick planks.

Temperature kept below 200C for a few hours, slowing increasing up to 400C by 6pm.

832C just before noon

The front steaming/smoking there was a layer of ceramic fibre laid along the top of the door bricks, to cut down the gap where flames had exited during previous firings.

The wind was blowing into this side of the kiln, which is not the prevailing direction, this meant the fired behaved a bit differently.

There were hardly any flames coming out of the gaps between bricks as the wind pressure was enough to slow that down.

Steve doing his fair share of the stoking! (Calculated on relative amount of pottery being fired!)

Bill demonstrating his new toy to Jennie.

The gun measures temperature remotely - as in from a distance away and with an accuracy that was in doubt!

7pm - at about 1100C.

The weather was changeable - thundery showers and patches of sunshine.

The stoking team taking a tea break.

When two potters meet, they chat.....

10pm, Jennie stoking.

The temperature had stuck at about 1130C for several hours!

Sam stoking.

The temperture got up to 1170C on the digital reading by 11pm and did not get much higher.

However the Cones 8 & 9 started to bend and were well over by 1.30am! That indicated the equivalent temperature of 1280C had been reached at the level of the spy hole.

The stokers finally left just before 3am, after an oxidising finish, a rapid cool for a 100C and then blocking up the doors and cutting off the chimney.

So it looks like the digital equipment needs checking!

Unloading Pots - 20th June 2016

The ceremonial removal of the first brick from the kiln door.

The front of the fired chamber revealed, with the brick door removed.

Most of the pyrometric cones are far enough over, although there are patches of coolness, where the glazes have not matured.

Close up of top of front.

Heavy reduction has taken place, with a good shine coming from a coating of fly-ash. The glazes are mature and are looking splendid.

Close up of bottom front.

The cones that could be seen through the spyhole during the firing can be seen half bent over.

Close up of mortaria at top of chamber.

This has picked up a lot of ash and is heavily reduced, so has a dark unglazed external surface.

This bowl was at the bottom of the chamber and was at a lower temperature, with less reduction, so stayed pale. The internal glaze - applied raw to the leatherhard pot has crawled off the top edge.

Back of the chamber.

Close up of the top back.

Close up of bottom back.

Beakers close to incoming heat from firebox, heavily coated in ash and reduced.

Other side of back of chamber.

Ash caught by rims sticking out into path of flames heading downwards towards exit tunnel.

The extra bag wall brick was placed to deflect the flames up into the chamber, rather than taking a short cut round into the tunnel.

A happy Janine with her pots (and one of Bill's mortaria with a base crack that she took to give a good home to.

Martin is either happy or delirious!

A line of Bill's mortaria and other bowls.

The light oatmeal and shiny white glazes were more creamy than usual, with perhaps a finer coating of ash all over, rather than coarser spotty effect.

A box of Bill's beakers.

The external unglazes surfaces have a good sheen, but some of the impressed patterns have been obscured by the build up of ash forming a thick glaze, where placed near the incoming flames.

The iron rich glazes have got a great sheen and some beautiful "Hare's fur" streaks.

The following images are of the work by various potters.

Steve's bowls.

The blushes of red are reduced copper glazes - enhanced by being put in a bright red box!

Bill's bowls in bottom of chamber at the back. Usually a cooler part of the kiln, these seem to have matured OK, if slightly less shiny.

Report and Conclusions

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The results were good, with some excellence and many happy potters! A few more cooler spots with immature glazes than usual, but some places with higher levels of ash. Heavy reduction in most of the chamber.

A fairly dense packing, with more small items than usual, maybe less room for the heat to travel through the kiln.

There was a build up of embers in one of the fireboxes in the early evening, when the temperature stuck at about 1100C. Bill was having tea so perhaps the team got too enthusiastic throwing in the wood! Also the embers should have been raked and riddled earlier, after the pallet wood had been burnt, which included the large chunks which take a long time to turn to ash.

A late finishing firing, mainly due to a lack of increase in temperature during the early evening, the reason for which is still being debated (or blamed on someone else!). Also because of the need for a long soak to mature the glazes really well.

The fuel was all dry - despite the showers - large old planks overnight (thanks to the J's for sawing that up into shorter lengths), then pallet wood, then to finish off the excellent old roof batten, so no blame there.

The weather was thundery, so perhaps the high atmospheric pressure stopped the chimney drawing so well as usual. Although the lack of flames coming out of the gaps between bricks, looked like a more oxidised firing regime. When the bung was taken out of the spyhole for a look at the cones, the flames were not so keen to escape that way. The wind blowing into that side of the kiln might be a factor, although it was a very gentle breeze at times. The wind increased late at night, which helped get air moving in the kiln.

The "team spirit" was better than ever, trainee stokers behaved well, with great efforts to help. Bill felt sleep deprived, but less physically tired - as he did not have to do so much hard work! The rewards were good with all the effort work it.

Comments are very welcome - email Bill Crumbleholme

Thanks to :-

Simon & Cliff and Hope Church for the roofing batten timber.

Pottery Class members for their support, Sam for his stoking and Jennie Hanrahan and her class for help filling the kiln and firing it.