Thinking Differently, Solar Power and Clay Making

I usually spend a bit of time making clay over the summer when the humidity is low and the air temperature is high. It’s a good time for drying out the clay slip after it has been ball milled.

All my so-called ‘clay’, is actually ground up igneous stones. I crush the very hard ‘granitic’ rocks in the big jaw crusher first to reduce them down to 12mm. gravel size, then through the small jaw crusher to get it down to sand size and finally it goes into the big ball mill for a few hours to reduce it to a very fine slip with water and 3% of Australian white bentonite. It is the only ingredient that I buy in for this home-made, locally sourced, native porcelain body.

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After ball milling, I test the pH and adjust it if necessary, it usually needs to be reduced a little, as the ball milling breaks down the structure of some of the felspars and micas in the stone. This releases tiny amounts of alkali into solution in the slip. The effect of this is to constrain the plasticity of the porcelain and inhibit the ageing plasticisation. Once adjusted to the correct level, the slip is stirred and then put through a fine sieve to remove any oversized particles and any foreign matter that has crept in during unloading. Thick slip is very slow to pass through a very fine mesh, so I resort to using a sieve vibrating machine to shake the sieve while the slip pours through. It’s quite amazing just how fast this process becomes with a little vibrational energy to keep the larger particles moving and not sitting and blocking up the fine mesh. ‘Vibro energy’ a really great focussed use for very small amount of electrical power.

Without the rock crushers and ball mills, I couldn’t make this local ‘native’ porcelain. In the past I always used to feel a bit guilty about using electrically powered machinery, as I was brought up in a family where ‘green issues’ were openly discussed, long before the ‘greens’ were invented as a political movement and ‘green’ came into the environmental lexicon. I’m not too sure what my parents actually called their lifestyle back then. Possibly ‘environmentally conscious’? Anyway, I’m happy to be called a ‘Greeny’ now and all that early environmental awareness has stuck with me. Give me the boy till he is 7! Now I am getting used to thinking differently about electricity as we are slowly becoming a fully electrified solar-powered household.

Electricity was always made with coal here in Australia and most of it still is. You have to specifically request to be put on a green power contract, and then pay a premium tariff for the pleasure of not using coal. 25 years ago, you couldn’t buy green power. Everything was coal, coal, coal, so I decided to make an effort to use the absolute minimal amount of electricity and we were very successful. We learnt to run a very lean electrical household. We have a very modest ‘LED’ screen television. A very efficient fridge that runs on 1 kW per day and a front loader washing machine, also very efficient. All in all we average an electricity usage of around 3.5 kWh per day. Very modest. We have chosen not to buy home theatre,  a dish washer or air con.  We have had solar hot water for the past 30 years, Solar electricity for the past decade and a Tesla battery since the start of the year. To the best of my knowledge, we have completely removed ourselves from the coal economy now.

When we did buy power from the utility, up until last year, it was always a battle to buy ‘clean’ green energy. They just hadn’t thought about it and weren’t prepared for the transition. It was a dinosaur industry. People like us wanted to buy clean energy, but they hadn’t put any plans in place to create any. It was all about business as usual. As the requests grew louder, some clean energy was slowly introduced, such that you could buy just 10% of your electricity as so-called ‘green power’, but it turned out that it was only hydro power from the Snowy Mountains Scheme. This was electricity that was always being generated since the 50’s and sold into the grid as part of the usual mix. But then the bean counters and ‘The Men in Suits’ got involved and thought why don’t we sell Steve Harrison the electricity that he is already buying, but sell it to him at twice the price. If he is silly enough to pay for it!  I wasn’t, so I didn’t.

We waited a long time, until the first wind farm was built just South of here. Then there was an offer that you could buy 20% of your power bill as wind energy, so we did, and continued to increase the percentage every year or so as more clean energy was built and made available. I remember that we were early adopters and had to go on a waiting list to get a higher percentage of clean energy. However, the energy company kept sending us supposedly attractive offers to change back to a cheaper dirty black power contract. This just reinforced to me that the market for green power was stronger than that for coal power. Apparently they had too much coal power and couldn’t get rid of it all.

Then there was government intervention to support the coal industry and then privatisation that was supposed to make every thing more efficient and cheaper. And what happened? The price went up about 200% here. A complete failure of market forces and competition.

Today I check in on our power usage on my phone app. I see that we are making about 5kW of solar power, not too bad, seeing that we are just a month off the winter solstice. We are only using a few hundred watts intermittently, that’s the fridge compressor switching on and off. There is a spike at 8am. That’s the toaster and electric jug for breakfast. It’s probably hard to live any kind of normal life and use significantly less power then this on a regular basis.

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Back to my clay tests and I pour them out onto the drying bed to stiffen up. Again I’m using solar and wind energy in this very passive way now to remove the excess water from the slip and reduce it to a plastic state. The sun shines for free every day. The wind blows most days, slowly the water is evaporated from the slip and it becomes stiffer and plastic. It’s gentle, it’s energy neutral and it’s free!

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Nice.

I’m very lucky to be able to live this rewarding, creative life in carbon constrained times. We are preparing ourselves for a creative, energy passive future, but it’s funny that trying to live a simple life gets quite complicated at times.

My New Book – 5 Stones

IMG_7383205 pages, 125,000 words, full colour, soft cover. Written, collated, printed and bound on the kitchen table. A very limited edition hand made book.

I have spent the last few weeks and months editing and formatting my new book. This will be my 6th book and 7th if I include my contribution to Handbook for Australian Potters.

This new Book is titled 5 Stones, and details my recent research into single stone porcelain. The book will be launched by Grace Cochrane at the opening of my show at Watters Gallery on Wednesday 16th of August from 6 to 8 pm. I have a selection of single stone porcelain from all 11 sites on show in the exhibition.

15 years ago, I discovered a white porcelain stone near where I live. It made me think about where else porcelain has been discovered and when. Over the past 15 years, I have travelled to each of the places in the world where porcelain was originally discovered/invented independently from first principles and found that they all had something in common, and that thing was a stone called ‘sericite’. It turns out that originally, porcelain wasn’t made from the white clay at all. Kaolin wasn’t involved. All the original porcelains were made from a special type of stone called mica.
My travels led me to China, Korea, Japan, Cornwall, France and Germany. I even developed communications with academics in California, Alaska and London. Then finally back to Mittagong in Australia. Near to where I started.  I have made my porcelain pieces out of these weird and interesting materials in remote villages, artist studios, back rooms, workshops, even factories. Where-ever I could track down and find amenable people using this ancient technique who were open to collaboration. 
At each site that I visited I made works out of the local porcelain stone, but I also used the opportunity to collect samples of their stone and posted these rocks back to Australia where I could process them myself and make local, contemporary versions of these ancient porcelains. I collected native porcelain stone material from 11 sites around the world and have made what I think are beautiful pots from them, both on-site, where that was still possible and back at home in my own workshop. 
This exhibition shows results of my firings and 15 years of research into these single-stone native porcelains. To coincide with this show I have written a travel journal documenting my travels. My book, titled ‘5 Stones’ will be launched at the opening by Grace Cochrane. The book stands alone in its own right as a travellers tale, as it has its own characters and arc of narrative, but also helps to illuminate the story behind the actual works on display in the show.
I have works in the show that were fired on-site in clean conditions to give very white and translucent pieces and I also have the same materials fired at home in my wood fired kiln with very different results.
4 of the 11 examples are made from porcelain that is no longer available, as 2 of the sites are lost forever and another two have complications.
I consider my self very lucky to have been able to get my hands on all of these ancient and very special porcelain materials. This will be the first and only time that all these porcelain ‘clays’ have ever been shown together in the one place.
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Unglazed and flashed wood fired Arita porcelain
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Wood fired and celadon glazed Japanese porcelain, fired in my kiln in Balamoral.
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Korean porcelain made onsite in Korea
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Woodfired Japanese porcelain
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My woodfired local Joadja porcelain, showing some carbon inclusion on rim and base.
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Korean porcelain stone body, woodfired in my studio.
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Amakusa porcelain from Japan, made in Arita.
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My local Joadja Aplite porcelain, wood fired with a lot of ember and ash contact. The intense carbon inclusion reduces the translucency.
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My local Joadja Aplite porcelain, wood fired with ember and ash contact.

Welcome home

We arrive back home at the end of Autumn. The pistachio tree has turned red in our absence and the liquid ambers are loosing their leaves. We head straight to the chook house to see how the girls have been faring without us. Perfectly well it appears. They have changed their allegiance to Annabelle Slugette, because she has been living here, working in the pottery and feeding them treats for the past few weeks. Hens live for food! I know that it is only cupboard love, but I do feel a little bit abandoned. I’ll need to find them a few snails or other special treats to win their hearts ( and stomachs) back.

 

We head to the garden to see what there is for dinner. We find our selves in that special period of the year when there are just a few summer vegetables hanging on, while the winter crops are just starting, so we pick the last zucchini and the first cauliflower. There are only a couple of weeks when you can eat this combination of garden produce. The chillis have ripened a lot more while we have been away, so we pick some and dry them.

 

The next day I’m back at work in the pottery. I have  to slake down all my turnings that have dried out while I’ve been away. Clay slakes down so much faster when it is bone dry. I have lots of small batches to deal with. I have been working on my collected samples of porcelain stones from all around the world and I have to keep all the turnings from each batch of pots made from each special rock completely separate and well-marked, so that I don’t get mixed up or confused about which is which. I have 10 buckets marked with masking tape and felt fen, so as to keep it all under control.

I start with the first 5 batches. I slake, blunge and sieve them all through a 100# mesh screen, then flocculate them and decant the excess water, it takes a while to get its all done. Eventually, they make it out onto the plaster drying tubs that I use for small batches of re-cycling like this..

 

I’m not just dealing only with turnings here. Many of my pots don’t even get to the turning stage. These ultra-fine, ground stone bodies, with virtually no real ‘clay’ content, based solely on mica and quartz, with just a little illitic material. Consequently, they have no dry strength. They sometimes just split as soon as they are placed on the chuck, some don’t even get to the chuck, as they split during drying. Other decide to part company with themselves after the first turning at the ‘roughing out’ stage.

 

Some others tear themselves apart after the second trimming. Only a few make it to the final turning and bisque kiln. The only good thing about pots cracking during drying, is that at least I can re-work the material and have another go at making something that might survive to the kiln. What happens in the glaze kiln is another matter. I’ll find that out for these samples soon enough!

 

Between a Rock and a Hard Paste

We have been sweltering here in 40 oC heat for a couple of weeks now. We were very fortunate to be blessed with 3 days of rain in the middle. It saved a lot of our plants from just shrivelling up. Fortunately, we don’t have any bush fires near here this time. However, I did start up the fire fighting water pump and sprayed water through the sprinkler system that I have installed on all the building here, in this case, on the pottery tin roof. I used it on the worst couple of days, to cool it down a little. It is good to run the pump every now and again to keep it in good working condition and cycle the fuel through the carburettor to make sure that it doesn’t ‘gum’ up.

I’ve been making use of the hot weather to crush and grind my collected porcelain stones. They have to be put through the big jaw crusher first, then the small crusher, then sieved to remove any over sized pieces and these are put back through the crusher again. Once it’s all of a suitable size, it goes into the ball mill to be ground down to a very fine paste.

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Once it’s out of the mill. I let it settle and flocculate for a few days and then remove any excess water from the top and it goes into a plaster basin to dry out until it is firm – sort of plastic. Except that it never really gets to be fully plastic. This is because it is just ground up rock dust and not clay. It does have a very small percentage of clay in the stone due to weathering of the minerals, but it is not a lot. It really takes years for this stuff to become workable in any normal sense of the word as potters might understand it.

If I were making bulk clay for stock, I’d be using the big ball mill and pour out the slip onto the drying bed on filter cloth. Once firm, I’d lay it down for several years in a cool dark place, but I don’t have that luxury on this occasion. I have posted these stones back from overseas on my recent trip. there are only just a few kilos of each sample, so the batches are quite small. Just enough to make a few pots out of each. I’d like to have more mineral to work with, but it costs about $100 to post a few kilos of stones back from places like Cornwall, Korea, China and Japan. So I have to work within my budget, as many countries have abandoned sea mail postage and the only option is now air mail. On one occasion, I was offered a cheaper option of ‘slow’ air mail. It made me wonder how the plane stayed up in the air if it was flying slowly?

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As these bodies are not aged, they respond to being worked something like ‘halva’! it just snaps if you bend it. It has to be coaxed along very slowly and gently, sort of seduced into changing shape.  I can’t even cut it in any normal way with a wire, it just tears! I can’t throw anything large out of this stuff, but I don’t need to. I only need a few excellent fired examples of the stuff to include in my exhibition at Watters Gallery in August, called ‘5 Stones’. This will be an exhibition of single-porcelain from all around the world, from the five places where single-stone porcelain was independently discovered and developed.

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When it comes time to trim the shapes into some sort of elegant form. The paste just tears and chips, instead of turning off in fine strips. The pot has to be very firm and almost bone dry to turn to a fine finish. However, I do need to remove some of the bulk of the weight from the base to get it to dry without cracking, so some leather hard trimming is necessary, and what a mess it looks to begin with! But it does clean up OK when it is dryer. I do struggle with some of these rock-paste porcelain bodies. I’d be a much better potter if I could spend all my time working with this stuff, but I have to do other things, like building kilns, to make a living. No complaints! I have a wonderfully creative, independent life. I’m very lucky. But I do suffer from the feeling that I could always do better. Nothing is ever finished, nothing is perfect and nothing lasts! This is reality.
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These dry rock dust bodies are so aggressive and abrasive, they make normal turning tools go blunt after just one pots is turned. I have to use tungsten carbide tipped tools to withstand the grinding effect on the cutting edge. The ‘clay’ is really just rock dust paste, so it is very abrasive to my fingers too! I have had to start wearing rubber finger stalls to protect my finger tips. Otherwise the ‘clay’ grinds off the skin from my fingers and they wear through and start to bleed.
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I’ve spent the past 15 years researching these places and going there, making contact with individuals and working in-situ, where that is still possible and also posting home the raw stones to be processed here in my workshop then fired in my kiln. This will produce a very different look and feel from the work made on-site.
I have written a book about my travels and porcelain experiences during this research. I have 90,000 words written, with just two more chapters left to write. It will be around 150/160 pages, in full colour, soft cover. I hope to have it for sale for under $50
It will be launched at the opening of my show at Watters Gallery in August.

Of Passata and Porcelain

The summertime heat brings on the tomatoes, zucchini, chillis, aubergines and sweet basil. They love this hot weather, as long as they get the water that they need. This means I have to start making passata sauce. We are now harvesting more than we can eat each day. This is just the start. At the moment we have to harvest the tomatoes each day in the small numbers that are ripening. It has taken a week to build up sufficient quantity to fill the boiler. This is the first batch of passata. Soon it will build up to 2 batches a week. I will continue to make this sort of tomato sauce right through the summer and into the autumn.

Tonight I’m making a small batch to start with for our dinner, so I’m including a lot of zucchinis and aubergines as well. This will be a sort of variation on the ratatouille theme. All these vegetables grow together, they ripen together and they taste so good together.

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I bring it all to the boil and simmer it for a few minutes, just enough to soften the zucchinis and egg plant chunks, then scoop out a bowl full each for dinner. It’s summer on a plate!

After dinner, I add in all of the other chopped tomatoes and cook it down into a sauce. After it cools I put it all through the mouli sieve to remove all the seeds and skins, then reheat and seal in pre-heated jars to keep for the winter.

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The other thing that I like to do in this summer heat is to make porcelain from my collected stones. They are so hard that I need to put them through the rock crusher first thing to reduce them down to grit, then I can sieve the grit and re-process the larger pieces to get it all to pass through a 3 mm screen, then into the ball mill to be reduced to ultra fine grade.

 From this I can make glazes and/or more throwing body, as required.

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The simple pleasure of a dull job

It’s that time of year again. I need to make some more wadding for packing the kilns. Making wadding isn’t fun. It isn’t even interesting really. If truth be told, it’s a rather dull job. It just has to be done. So, to make it as bearable as possible, I make it up in a monster size batch, so that the pain is all in one go and then there is the relief of knowing that it won’t need to be done again for another year.

Wadding is used to seperate the pots from the kiln shelves and the kiln props from the kiln shelves. It has to be refractory and remain crumbly and friable after being fired to stoneware temperatures, so that it can be removed easily, even allowing for the deposition of the fluxing effect of wood ash during the firing.

I make it up in big batches of 120 to 150 kilos. Every wood-firer has their own ‘secret’ recipe. I don’t have any secrets. They’re all up here on this blog. Some potters use various mixtures of silica and clay, but I don’t want to use fine silica dust anywhere if  I can help it, because of the risks of silicosis. Others use alumina powder and clay, which is very refractory, but expensive and in my opinion it is overkill. There is too much of an embedded energy debt tied up in aluminium and alumina processing. It takes massive quantities of electricity to extract aluminium from bauxite, most of which comes from burning coal, so it is rather unethical to use alumina powder, unless it is absolutely necessary. We use a small amount in shelf wash, but it amounts to just a kilo a year. I can live with that.  The other thing that I really dislike about alumina in wadding is that unless you are particularly careful, you end up putting stark white finger prints on the pots that are being packed after handling the wadding. You really have to wash your hands after every time you touch the stuff.

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I have decided to make this batch of wadding out of ‘fat’ sand. Fat sand is also called ‘bush sand’,  ‘brickies sand’ or ‘bush loam’. It’s a coarse quartz sand with a fair amount of clay in it. It also contains some limonite or hydrated iron oxide, so it looks a bit yellowish. I mix this with some powdered kaolin. This is a great use for powdered kaolin. I don’t use a lot of it, but is is very useful for this purpose. I mix it in the ratio of one 25kg bag of kaolin to 4.5 buckets of damp washed sand and one bucket of water. When I can get clean saw dust I also add two buckets of saw dust, but this is getting harder to find these days. The last time I visited the local timber yard, they had been cutting some synthetic wood products that were a rich canary yellow. This stuff looked like it was loaded with resin glue. I thought that it might be particularly toxic if it were burnt in the kiln as wadding. So I didn’t collect any.  So, this batch of wadding is just going to be sand and clay.

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Adding saw dust is great for wadding that use on new pots that are once fired, as it can leave an interesting charcoal grey to black shadow mark. It doesn’t work on bisque, only once fired work.

When it is freshly made wadding like this is rather short or non-plastic, being so sandy, but after ageing for a few months it develops quite good plasticity and after a year or so, the last few bags are plastic enough to throw with. Not that you would want to, but I think that it might be possible. I’m down to my last bag of the old batch now and it is very easily worked into coils and small balls. This new batch will have a month or two before I need to use it.

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I make it up in a couple of batches in the dough mixer and then bag it up into 15 kg packs and store it away.

Security is a years supply of wadding.  Now, when I look down on my stash of wadding I get the simple pleasure of knowing that I won’t have to do this job again for another 12 months. It’s a nice feeling!

fond regards from the well wadded potter.

 

A Trip to the Mountain

We are taken on an excursion to the mountains. It’s a foggy moist kind of day with intermittent rain showers. On the way we pass a really obvious white pegmatite dyke in the side of one of the hills near the road. I’m keen to stop and look, but it appears to be on private land and there is no easy access to it. We drive into a trucking company’s yard to get a closer look, but it is still a bit too far away and it is raining. I don’t fancy bush bashing in my good ‘going out’ clothes. So we let it pass for today. I may try to come back here if there is time on a fine day.

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We press on over the mountain top, past a very pretty water fall. Yesterdays rain has brought it to life today. It wasn’t flowing like this the last time that I was here.

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We go to Okawachiyama for a 2nd visit. I don’t mind, I’ve been here before, but Janine hasn’t. It’s a pretty place and there is always more to see. You can’t see everything on one visit. There are still lots of lanes and little walkways to explore. This remote valley once housed the Nabeshima Clans’ potters. They were held here in captivity to create the finest, whitest, polychrome enamelled porcelain. They managed to find the whitest of materials and restrict their use for the shogunate only. The creamy white clay glaze combination that they created is still a wonder to this day. It’s purity and translucency is just remarkable. I went on a geology tour of the local porcelain stone sites last week with Kanaiwa san. We visited many places around this district, but we couldn’t find the lost kaolin mine of the Nabeshimas. Kanaiwa san has made a life long study of the ‘nigoshide’ white effect. He has managed to make a modern synthesised version using 3 of the local varieties of porcelain stones. I don’t know his technique, but his knowledge of froth flotation technique that be came obvious to me during one of our early conversations, leads me to believe that there might be some fertile ground there for experimentation. I have certainly found it an essential way to remove iron from otherwise ‘dirty’ rock samples back home in Australia.

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On our walk up the steep Okawachiyama Valley road, we call in to see one of the last ladies that  can do the seamless cobalt background brushwork. It is a very difficult technique and is now almost lost. These days this kind of background is either sprayed on, or transfer printed. Of those who still hand paint the ‘gosu’ cobalt blue background. and there are only a few of  these left as well, the technique used these days is to gently squeeze the ‘fude’, pronounced ‘foo-day’, brush to control the flow of the gosu pigment and loop the brush tip back and forth, producing a layered, slightly overlapping, background pattern. The Nabeshima technique used here is to hold the brush by the handle, not the hair, so no squeezing is used, They tilt the brush, up and down, to control the flow of the pigment. It is a truly astonishing technique.

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