Solar PV Fired Pottery Kiln

We have been creating a life here for over 40 years, living as much possible as off our few acres of forrest, orchards and gardens. We have spent a lot of personal energy in converting all our energy needs, to wood fired everything. We have chosen to leave half of our land as forest, and there are always trees that are maturing, dying and falling over in that forest.

We haven’t harvested all the trees that have fallen on our land, as there are too many, so we have left the ones in the most remote locations to rot, as it was just too much effort to make a track into the bush to get to them out. If a tree falls in the forrest – does anybody hear? No! That is line from a song. If a tree falls and we let it rot, then it ends up the same as if we cut it up and burnt it in the house oven or kiln. The carbon that was taken from the air and soil, returns to the air and soil, only just a bit slower with composting than burning it in the kiln. Composting is a slow form of combustion.

Having spent a lot of thought and energy converting our life over to non-fossil fuel energy, we now find that with global warming, the fire bans start a month earlier and go on for a whole month or more longer in the autumn. This has caused us some trouble lately, as we have had to cancel the last few, late winter/early spring wood firing workshops here in the past couple of years.

So, if this new warmer future is to be our new reality, we had better make plans to adapt. Well we have. Starting 13 years ago we decided to go fully solar on our house and workshop and haven’t paid an electricity bill since. Those early Australian made solar PV panels have now paid for themselves, and from now-on we will have free electricity for the rest of our lives.

We live so frugally in our home these days, that we have found that we can now live on a quarter of the electricity that we used to. We have done this very simply by introducing efficiencies. As old appliances wore out, we replaced them with very low energy newer models. It’s not hard to do, but it takes time and a lot of research. It has taken time because we didn’t just throw out working appliances. We waited until they died of old age. There is so much embedded energy in electrical goods, that it is a crime to replace them before they are worn out. We have reduced our daily energy consumption in the house from 11 kW/hrs per day down to 2.5 kW/hrs. This means that there is now a lot of excess, clean, solar electricity that we can use to fire our kilns cleanly and efficiently.

As we now have a problem with firing the wood kilns all year. I have decided to convert all our Electric firing over to solar PV.  I have built a new light weight, portable electric kiln from very low thermal mass materials. I have included a couple of small LP gas pilot burners into the design, to allow me to create reduction atmospheres after 1000oC with tiny amounts of LP gas while the solar panels and the battery fire the kiln load of pots up to Stoneware.

There is nothing earth shattering about this. Korean, Japanese, and Chinese potters that I have met and worked with have been using a combination of LP gas or wood fired electric kilns for years.

This is my version of the idea. Light, flexible, portable, low energy and suitable for solar PV and battery firing.

It didn’t hurt that I was able to build it totally from spare parts and waste material that was left over from my many years as a kiln builder. I only had to buy a thermocouple for this kiln, as the old-fashioned temperature controller unit that I had sitting in a box for the past 20 years, needed a specific thermocouple to make it work.

I find it amazing and very rewarding to be able to convert a few boxes of  old ‘rubbish’ that other people had thrown out, plus some left over material, and turn it into an amazing, functional, energy-efficient, working kiln.

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I had a couple of sheets of stainless steel left over from other jobs.

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I have been storring a few sheets of ceramic fiber for over fifteen years. They are left over from a glass kiln job that I did many, many years ago. They are pre-fired, pre-shrunk, hardened and ready to use for a job just like this

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I even find that I have a shrink-wrappped coil of Kanthal A1, element wire sitting in my store.  It’s been there for years. It was left over from a job that I tended for, but which never materialised. I spend sever days working on these new heat flow and emisivity calculations to get the best answer for what I have in stock, compared to what I really want to achieve. After 5 goes at the problem, I have generated many pages of mathsand enough energy to warm the kitchen when I’m working and re-working out all the perameters. I eventually get a good answer that I can live with. I have to make a new mandrel for my lathe to suit this job.  I find that I can use some of the left-over stainless steel fire-bar material that I still have from the little portable wood fired kilns jobs of the last few years. It turns out to be just about the exact size that I need. I alter my calculations and go ahead and use it.

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When I go looking, I even find that I have a few control pyrometers and a couple of infinity switches to do the basic job of controlling the kiln. It’s not an electronic, solid state, ramp controller, but it will do nicely. I will have to do the first few firings in conjunction with pyrometric cones viewed from the small circular spy hole.

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After a few weeks of part-time work, fiddling away in my spare time. I have what I think might be a functional kiln. I have sifted through several piles of ancient junk, destined for the re-cyclers. I have discovered a lot of functional bits and parts that I wasn’t very interested in using 20 years ago, but which I can see potential in now. So many potters wanted to have their kilns converted to electronic ramp controllers in the past. I did the conversions for them, but couldn’t bring myself to throw out a perfectly good, working order, analogue kiln control unit. I’m now glad that I persevered, and storred all this junk for so many years.

I’ve found that I have enough parts to build two kilns, so I probably will. This first kiln is designed to be very low thermal mass, firing to stoneware on solar PV + with some back-up later in the day, as the sun goes down, from our Tesla Battery. I have a couple of very old, but un-used, brand new, pilot burners, these are so old that the company that built them has now ceased to exist. My plan is to use these two tiny pilot burners to create just enough CO2 atmosphere to give me adequate reduction, while the elements powered by the solar PV fire the kiln.

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I’m hoping that it will work as I planned. Only time will tell. Watch this space.

It’s been quite good slowly fading into semi-retirement. Cleaning out years of old boxes that I had forgotten about on that dusty top shelf. There were two whole kilns stored away in the form of spare parts.

 

The Yanggu Porcelain Museum wood kiln firing

After we have spent out time in Seoul, we set off to travel up to the geographical centre of Korea, right up against the DMZ to a small town, or large village, called Bangsan. They have been mining porcelain stone here for centuries. The earliest written records of porcelain making in this valley date back to 1391. The ancient kiln site is now preserved under a roof, but still accessible. The site where the porcelain stone was stock piled and sorted ready for shipping to Seoul is still there, however, it has been desecrated by someone in living memory. I don’t know the exact details or circumstances, but what a shame. The Korea war raged up and down the country for a few years, back and forth. Maybe it was then? I don’t know.

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There is a very ominous sign post on the banks of the river just 50 metres from the back entrance to the Porcelain Museum. It looks to me to be a warning sign about land mines. I get out my phone and use the translation app to read the text. Sure enough, it tells me that land mines can still be found here exposed after floods or washed down off the hills after heavy rains. It tells me how to identify them and not to touch them. As If! I can only suppose that some small kiddies might pick one up if un-accompanied? We are so lucky in Australia.

Our trip up here took us all day on 3 different busses and about 6 hours with waiting for connections. We have arrived early, before the forum is due to start, as we want to put pots in the long wood firing that will be held in conjunction with the conference. The Museum has a couple of 5 chamber traditional wood kilns that are fired a few times each year.

We pack all day and work into the night. One of the residents potters living in the student accommodation village ‘Daewoong’ is in charge and is assisted by a visiting potter from Poland ‘Gosia’. Not her full name, but one that she feels that we can pronounce. The firing will go for 100 hours or 4 days, all through the forum and demonstration days.

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On the days when we are not involved in the forum, we do a 6 hour shift in the stoking. Janine ends up getting in more time at the stoking than me, as I’m constantly involved with the translator and publisher, or if not with them I’m speaking at the forum. I turn up one day to find that it is a fully female crew on shift.

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As the firing progresses on to the final stages and the side stoking of the 5 chambers.

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Cornwall and Devon

After leaving Wales, We drive to Cornwall to meet up with our old friend Joanie. It was Joanie who volunteered to be my ‘get-away-driver’ last year on my last visit. This time we know where we need to go and what to do to collect another few kilos of Sericite porcelain stone. It’s a trivial matter this time, rather than the week-long epic of last year.

While we have a few days with Joanie, we decide to walk over the causeway to St Michael’s Mount. It’s a really interesting place, we end up spending the entire day there and miss the return tide window of opportunity, so have to catch the small boat back at high tide.

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The tide comes back in while we are still at the summit and we see people wading back  across the causeway in chest high water, until it becomes impossible.

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We enjoy lunch and afternoon tea on the island taking in the full tour of the old house/castle. A really enjoyable and informative day taking in all the history of the ancient site.

After a few very relaxed days with Joanie, we move on to Devon to visit our friend and fellow wood firer, Svend Bayer at this new pottery kiln site in Kigbear. Svend has decided to sell up in Sheepwash and move on to the next phase of his life. We really love the ancient thatched roof, cob cottage in Sheep wash, but times change, as do we, everything changes. We must adapt. It really is an exquisite place. So romantic!

We are lucky enough to get to see assembled, an amazing collection of Svend’s best works, collected over the last few years of firings here at Sheepwash.

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We are totally privileged and very lucky to turn up at just the right time to see all these wonderful, master works, before they are all exhibited and sold.

Svend’s new kiln, as might be expected, is pretty big. There are 5 potters sharing the kiln  firings at Kigbeare with Svend. It’s his way of training the next generation of wood firers, passing on the baton, by mentoring these lucky, and committed, next generation potters. It’s a huge kiln!

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We are lucky to turn up on the day of the un-packing of the kiln. There are pots everywhere. So many nice things to temp us. It’s the end of an era and the beginning of another. We are so lucky to be here to experience this moment.

We spend a few days here. The next day Svend takes us to see the local Museum at Bideford, with a great collection of local earthen ware pots.

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Earthenware pots have been made here for hundreds and hundreds of years. This is the home of the famous Fremington terracotta clay.

We call in at the Post Office after visiting the gallery, as the post office is just across the road. I have 5kg of sericite porcelain stones in a cardboard box all taped up and ready for post. I can’t carry this extra weight home on the plane. Svend is visibly shocked to hear that I just paid Au$250 for postage! he enquires how I can do this? I reply that last year I did the same and when I got home I processed the stones into its unique porcelain body and managed to get 3 very good pieces out of the firing. I sold them for $900, $750 and $500 respectively, through my Show of ‘5 Stones’ at Watters Gallery in Sydney. They were nice pieces and found good homes. The return covered the cost of the postage, but not the 3 months of processing, making and firing.

Still. I don’t do this to make money. If I wanted to make money, I’d have got a job. I want to live an interesting, engaged and well-considered life. As long as we can get by, I’m happy.

Tomorrow we travel on, making our way slowly back towards London.

Coals to Newcastle

Here we are building a kiln in Stoke on Trent! What could be more strange than for us to travel from Australia to Stoke-on-Trent to build a kiln?

The staff and students at the Clay College are all really great and we all get along really well. We are billeted with staff member Richard Healey and his wife Lucy – who is a chef. WOW! Great food all week. A really lovely couple. It must have been a bit stressful for them to have a couple of total strangers in their home for 2 weeks, but we got along very well. We had a great time. I hope that they have recovered.

They live in an amazing old house called the ‘Flax Mill’, that has its own little stream and pond, on a site that goes back well before the English civil war. A decisive battle was fought right here on these grounds. There is a monument in the adjoining paddock. This is some kilometres out of Stoke, and is the site of our kiln building experiment. Lucy is setting up a cooking school on site and Richard has his studio, where he makes blue on White contemporary hand painted and thrown porcelain. Beautiful work. If I lived locally, I’d be enrolling.

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We spend a week in the construction phase, mostly laying bricks, Then I give a master class on kiln building at the college on the Saturday. This is open to the public and is fully subscribed – which is pleasing.

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All the students flat-out, hard at work bricklaying!

Janine and I spend the Sunday at work on the kiln by ourselves, cleaning up, but most importantly doing a lot of the welding on the steel bracing that will be necessary to completely support the kiln structure while it expands during firing. It’s a lot easier to do this welding while there isn’t anyone else around.

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Janine and Grace volunteer to get into the firebox and throat area of the kiln to wash the floor of the kiln with alumina kiln wash. A shitty job. Thank you!

The packing and firing goes pretty much to my expectations, although Janine did overhear some chat about people expecting to have to fire for 40 hours. When I was asked what to expect in terms of firing time I said that I expected to fire for around 12 to 14 hours. If everything goes well. However I don’t know anything about this wood that we have to use for this firing. So it might take a little longer. As it turned out the firing lasted for 13.5 hours and the results were good for a first firing. I left them with the recommendation that they should plan to fire the kiln again a second time, as soon as possible, without me being there to advise, while it is all still fresh in their minds.

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The firing can be very clean when using a down-draught style firebox like the Bourry box that I have developed to a such a sophisticated standard. When it comes to side stoking the main chamber, there is inevitably going to be some smoke and this needs to be managed carefully. However, when the time comes to drop the last remaining butt ends of the sticks into the firebox. There is a brief moment of quite intense smoke as the amount of fuel outweighs the available oxygen for about 1 or 2 minutes.

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While we are in Stoke, we make time to go to the local Museums. First we take the tour of the Gladstone pottery Museum, which was good, an excellent experience. The working conditions of their employees must have been horrific back in it’s hey-

day. A time long before any thoughts of OH&S in the minds of the factory owners and government.

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For me, brought up in Australia, it’s really interesting to see actual bottle kilns. There weren’t that many of therm here in Australia. I am of an age where i was able to see the old ‘Fowlers’ Pottery in Marrickville in Sydney, before it was torn down. I ended up with a truck load of dense fire bricks from their old bottle kiln and they are now incorporated into my wood fired kilns here.

We also spent a long time in the city museum where we saw a really extensive ceramics collection. Amazingly, it is here that we finally find a collection of pots made in the Plymouth Pottery Works by William Cookworthy from the Tregonning Hill, Sericitic, weathered granite.

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This is the best collection of Cookworthy work that I have seen. The V&A has nothing and the British Museum, only has one piece.

After the unpacking of the kiln, I get a nice little wood fired cup out of the firebox area.

A sweet little thing to remind us of our working holiday trip.

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Another Little Portable Wood Fired Kiln Leaves the Workshop

We have been keeping busy rolling out the latest batch of little portable wood fired kilns. Another little wood fire Gem leaves for a new life of fun and fulfilment for another potter. All the remaining kilns are set up with gas burners for dual fuel firing.

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I spent most of last week making the burners and fitting them to the kiln on removable mountings that slide into place when needed.

These are the last of the first batch and while I wait for collection of these first orders, I start on the 2nd batch. There isn’t enough room in my small kiln building workshop for more than seven kilns at a time and still be able to move around safely and engage in productive work.

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I go to the garden after work and pick a load of vegetables for dinner, do a quick bit of weeding and do a little watering, as it is still incredibly dry with no rain storms to speak of for 14 months. The dams remain dry.

I cook a fresh snapper for dinner, steamed on the stove top in a big frypan with a little garlic, lemon juice and white wine.

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Wood Cutting Working Bee

We have recently had 3 big dead eucalypt trees removed by our local arborist. One was struck by lightning, and the other two were killed by mistletoe. We paid the minimum, to just have them dropped to the ground. We took it on our selves to cut them up and remove all the blocks to storage and seasoning.

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We spent several days cutting up al the logs into small sizes, such that we could manage to move them. Janine and I spent a week whittling away at the big number one log and   finished the first tree by ourselves, but then had the wonderful assistance of some friends and pottery students for a day.

We have been so lucky to have these people volunteer their help for a day and come along to give us a hand in shifting all the logs that Janine and I had spent the week cutting up. It’s a huge task to lift and load several tonnes of wood and then shift it and stack it for seasoning.

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This is all very vigorous work and we sweat copiously in the heat. The larger, straight pieces were all cut to kiln size ‘hob’ length, while all the scrappy, small or bent pieces were all cut to 200mm. length for splitting for the house kitchen stove. The main central log was over 600mm dia. So it was too big to manage at ‘hob’ length of 700 mm. So I cut it to 200mm. just so that we would be able to manage the lifting and stacking. I rigged up a couple of planks , so that we could roll the bigger lumps up onto the truck to be carted to the wood shed and splitter.

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This should keep us going for a few years in the kitchen stove.

All the smaller dia. logs were cut to ‘kiln hob length’ of 650 to 700mm to suit the fire-box of the kiln, and then stacked for seasoning. A year or two should do it.IMG_0752

There is about 7 or 8 tonnes in this load of 19 stacks about 1200mm high.

 

The First of This Years Little Wood Fired Kilns Goes Out the door

I have been busy working away at the first batch of little portable wood fired kiln for this year. I had too many to fit in the workshop in one go, so divided them into 2 batches. The first batch of 6 is almost finished. I had to finish one in a hurry to catch the boat to Tasmania last week.

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The rest of the little ‘Daleks’ are calling out “incinerate, incinerate!” But they are toothless, as I haven’t welded the stainless steel fire-box grates or made the burners as yet, so we are all still safe. They still need another weeks work on them to fit out all the additional features, but he main body of each of them is complete.

IMG_0721If you are one of the dozen people who contacted me and asked to be on my build list for this year. This is where I am up to. I will be contacting the first 6 customers who have paid their deposits in the next week or so.