Category Archives: Kiln Firings

Errmm….Hi Al, have you got an angle grinder?

Luckily he did, since all but two pots in yesterdays firing had welded themselves to the kiln shelves.  For some reason (this is a glaze I have used before and it didn’t happen last time!) the glaze ran off the pots during the firing and when I opened the kiln this morning, they were certainly not for budging.  After a severe beating with a wooden stick, some came free willingly, others came free leaving large chunks of the foot-ring still stuck to the shelf and one poor soul is not going anywhere…he is now part of the shelf…no amount of beating or grinding is going to set him free.

By some twist of fate, the only pot in the kiln that mattered came out unstuck and unscathed. A lily bowl commission for a friend’s wedding gift, I don’t actually know the bride Janet…..but I feel like I do…..so I very much hope she likes it…when she finally get’s it.

Am pleased with the results of some of the slips, especially the Maryport slag.  This may need a second firing, but the iron in the slag has done magical things with the turquoise glaze.

The crater glaze is amazing…..love it….will be brilliant over black slip.  I have been carrying the bowl around with me all day….I can’t believe it, something that came out of the kiln like it was supposed to…in fact much better than I had thought….may even tuck it under my pillow tonight…or is that taking things a bit too far?

"Help....I'm Stuck!!"......"humm..you ain't going nowhere!"

ha ha...I'm free, but oh no...I have shelf stuck to my bottom....

That's it....get to work on my bottom with the angle grinder...gently now!

Lunar Bowl. Love this crater glaze (more on this later)

Maryport Slag pot

Lily Bowl commission for Janet's wedding pressie

Vase with Stoneycroft Ghyll Slip

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Wood Fired Bowl

Liberated the bowl from the wood firing kiln and very pleased with the result.  The celedon glaze is more green than I would have liked (I don’t like green!), so less red iron oxide next time.

Really like the rim, where I used black slip.  The glaze was probably a bit thin too (fine line).  The other bowl didn’t make it into the pack, so a chance to put another layer of glaze on before firing in the gas kiln on Sunday.

Great to see everyone elses work turning out so good too…..another success for Bertha chalked up.

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Bertha

As if it wasn’t hot enough on Friday (hottest day of the year so far), I spent the whole day at the UCA firing the wood kiln with the Kiln Club (I am now a member!)…..What a great day we had.

The wood kiln, affectionatley known as Bertha, was lit at 4.30 am (I wasn’t there for that part).  She consumed more than 1/2 tonne of wood during the day, before finally reaching the desired temperature at about 9.30pm.

This was my initiation into the world of wood firing and I can see why people get hooked.  You are involved in every part of the firing, obsessing about the temperature rise, the shape and size of the pieces of wood.  Stoking is a constant and precise process, it doesn’t pay to take your eye off the ball for a moment.  For a big old kiln, the sensitivity was amazing.  There are the long periods where it just didn’t seem to rise in temperature at all, and it felt like it was stuck at 1100 degrees for a couple of hours.  A bit of tickling here and there with the dampers and mouseholes, some gentle adgitation, some carefully chosen pieces of wood and the break through came.

Interestingly the bottom of the kiln was considerably hotter.  Cone 10 was down by the end at the bottom and the middle, however at the top it finished up with cone 9 bent half way.

A kiln club member cleverly brought some potatoes, which were perfectly cooked in the embers..delicious.

A met a really great group of people, and look forward to the next firing.  The kiln should be opened on Thursday, so am intrigued to see the result of my Celedon glazed bowl.  Whatever the result I gained a lot from the experience.

Sealing up the door

Stoking

Raking out the ash box

Watching the wood pile quickly diminish

Tucking into jacket potatoes cooked in the embers

Raking out the ash box

Clearing the ash box..agian. Towards the end when the kiln is consuming so much wood, this is a regular and very hot job

Checking the top cones and revelling in the large reduction flame

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Phew….last firing…

Great colours appeared from our last firing of the week.  The oxidised firing produced a lovely turquoise and pink.  We managed to see the cones this time, cone 7 and 8 bent and cone 9 just going, Decided not to soak and it ended up with the pyrometer reading just a bit shy of the desired temperature.

Good test pieces, think I need to focus on the form of the pieces now to show off these glazes to their best.

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Overcooked It

Second kiln firing of the week and I think we overcooked it.  Tried an oxidised firing this time, to see if we could get turquoise, green and pink glazes.  Learning that the temperature inside the kiln varies greatly. Opposed to what you would expect, the front left, bottom of the kiln seems to be the hottest and the back of the top shelf the coolest.  I always thought that heat rises so it would be hotter at the top, but this doesn’t seem to be the case.  Will have to investigate further.

The three bowls from the throwing workshop 2 weekends ago do seem to have survived, although the pink glaze was definitley over done.  On a positive note, the experiment of glazing over black slip had a very pleasing effect, so I will continue to develop this.

The temperate rise was a bit slow throughout the firing, aiming for 1500 per hour and although the top temperature was 12630 and the guide cone 10 was still upright when we finished increasing the temperature, it must have bent over during the 30 minute soak.

Everything make from the black clay, max firing temp 12600, was very over fired.  Imagine a roast potato that had been on max in the oven for 5 hours…… so we now know not to do that again…..no pictures of these pots…not a pretty sight!

Learning more with each attempt, still only 3 firings under our belt……  I know how it feels to be over cooked, so does the poor doggie, went for a walk near East Dean on the South Downs Way….it’s been a scorcher today, luckily we were in the woods.

Last firing tomorrow before the craft fair…..lets hope we’ve learnt enough this week to make it a good one……

Great big canker, wrapped all the way round the tree

Hot doggie...think she might be a bit overcooked too!

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Second Firing Results…

Some really good results from the glost firing. The salt pig glaze has worked particularly well producing a high gloss finish.  It’s a shame I now only have one of these, the other one’s bottom blew off in the biscuit firing.  In fact the same thing happened with a custard jug, a vase and two bowls, so I have been panicking about having enough to fill a table next weekend.  I am sure they were completely dry and although I can’t be sure they didn’t contain air bubbles, that’s quite a lot of pieces to explode, especially since it occured during different firings.  I am boycotting that particular type of stoneware now clay…..I think it’s to blame as someone at the pottery experienced the same problem…at least it’s not just me.  Am planning a trip down to St Agnes at the end of June to pick up some lovely Cornish clay.  I just hope the clay pit is open on Saturdays.

Interestingly the celedon glaze I made worked well on the small jar, but looked totally undercooked on the mug.  I presume it is all to do with where the pieces are located in the kiln, and knowledge of this will come with more experience of firings.  The jar was by the burner on the bottom shelf and the mug on the top at the back.  The other mauve glaze looked slightly underfired too.

All three cones were down (7, 8 & 9), although according the pyrometer the temperature only reached 12630c.  Cone 9 shouldn’t have gone until about 12800c.  The temperature rose steadily at 1500c per hour for the whole firing.  Next time I think we need to slow it down towards the end and allow for 1 hour soak time.  Not bad work though for only our second ever firing…..will be getting a lot more practice this week.

Salt Piggy

Small and large Duck Bum Bowls

Barium blue glaze over pale ash glaze

A quartet of colanders

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Firing in the Rain

It’s bank holiday….so of course it is raining.  Despite the rain we continued with the plan to fire the kiln today.  There is a tight schedule to get everything fired before the craft fair next Sunday.  This is the first of three planned firing this week, so really hoping we get off to a good start.  I am using new glazes, never tested before, so taking a risk that they turn out well.  It’s too late to make any new pots if something goes wrong.  It will be extra exciting opening the kiln tomorrow.  Julian had his graph out again today and ignoring a blip at the start, he is confident it was a good firing, lets hope he’s right……to be continued…..

Kiln packed

Trying to shelter the flu from the rain and the burner from the wind.

This is fun.....

Looking for cones is the only reason you would need sunglasses today

Gas pressure and burner on full this time

Reducing flame

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