Wednesday, October 14, 2009

A Raku Kiln for Armelle, getting pots glazed for firing

A Raku Kiln For Armelle

Firstly, greetings to new followers, and to new people who have commented recently. It is really lovely to feel a part of a supportive community of people who are interested in pottery, art, writing, and so on, and like to share ideas. Armelle commented recently and mentioned that she was making a raku kiln. I have included a plan of a simple raku kiln with this post for her, and for you too! If you click on it you should find that you can read the text OK.

Raku kilns are rather fun because they can be made out of recycled materials. All sorts of designs will heat to around 1000 degrees Centigrade, and it is possible to fine tune a design, like the one that I have illustrated, to get up to 1100 degrees or so by better insulation and increasing the height of the chimney. In fact it is a really good idea to try out modifications of your own, and to find out what works and what doesn't. This design is very similar to that of the first kiln I made that is shown in the photo below.

My first kiln under construction

The kiln I use now for raku is different again. The firebox goes across the end of the kiln, and the kiln chamber is built on something solid in stead of being just a kiln shelf over the fire box. If I get time, I will draw up a plan for this design too.

My current raku kiln

This week I am getting pots glazed and ready for a firing of my wood fired kiln.

Applying liquid wax to the teapot to where the lid will sit.

Glazing the inside of the teapot. Teapots all have their first pour whilst being glazed.

Some copper red jugs

I made a useful discovery the other day, after a careful test of one pot, that a whole batch of copper red pots that were under fired in my last wood firing, could be transformed by firing them in the electric kiln! The pots had been an unpleasant sugary heavy liverish red, and really benefited from the oxidized refiring. All sorts of lovely shades of red, purple, blue, green were achieved.

Laura made this lovely arrangement of spring flowers from her garden. We had it with the pots in the studio when we were open on Sunday.


paul jessop said...

Hi Peter, the pictures are great, I love the colours your getting in the Raku kiln.
I had a visitor in my showroom who knows a potter in New Zealand his name was Barry Brookham. I thought she was going to say Peter.

Linda Starr said...

Once again you are so generous with your kiln plans. The minute I saw your wood fired raku kiln I in the first post I was thinking I wanted one. Can't wait to find our new place so we can get started on one. You really need to compile all these plans into a book - I would be the first person to buy the book. Lovely spring flowers and a great group of teapots. said...

Wow, you like to do things the hard way, don't you, wood and raku! Whew, lots of hard work!! I love the raku kiln, wish I had seen this before I bought mine! Hey, I have a technical question for you. I am trying to come up with a turquoise glaze to go with my raku glazes but I want the inside turquoise and don't know how to make it food safe. I understand that using copper carb as a liner is not safe. But, I remember you posting some beautiful blue bowls a while back. How are these food safe? Any thoughts......Happy firing! said...

I left out Earthenware in the above question. trying to find an 04 glaze that is turquoise that can go inside, is this possible?

Angie said...

What a wonderful display or Tea Pots ... cant wait to see them fired.

I love reading your blog and having a glimpse into your life. I am also learning a great deal about a suject that I had only touched on, so long ago. I even looked up pottery classes the other week but there are one or two and they would only be accesable if I had a car.

So glad my last post made you smile!! ...I love this blogging and the friends we make

Armelle said...

Wow.................thank you very much Peter, you are so generous..............Yes You have to compile your plans and make a book, how can I ever thank you?

Your tea-pots are so lovely !!! I am so glad to see this is spring for you, when we are going to automn and winter, it's so amazing !!! all these days summer doesnt want to go away and the weather is beautifull and sunny.

Best wishes and thanx again


Peter said...

Hi Paul,
Lovely to hear from you. Hope you have been able to get away for a few days after all your activity over there! I'm almost willing to bet that the potter the lady referred to was Barry Brickell, who lives up at Coromandel in the North Island of New Zealand and works predominantly with his local earthenware clay. A mighty man of potting and engineering in this part of the world, Barry has built a railway at his place! /

Hi Linda,
It would be fun to put a book together one day (I think...!). When you do find a place to put roots down, I'd love to send any help I can for a kiln. In the mean time, enjoy your travels!

Hi Tracey,
The food safe thing and raku seem very hard to achieve when it comes to copper based glazes. Low temperature glazes do drive me a bit crazy as they can look so nice, but be rather impractical.

I posted about earthenware glaze tests and recipes on April 19, 2009

The aqua blue that I have used in earthenware is adapted from one by Janet DeBoos. I greatly lowered the amount of copper that was in her glaze and added tin oxide to help produce reds in reduction (which it will do), and some china clay to slightly raise the maturing temperature to that of my clay. Her glaze was cone 05-03, I wanted mine to mature at cone 02. If you want yours to mature at cone 04, just take out the china clay and see if it fits your clay OK.

I like the petalite content of this glaze, the lithium contained in it will help with glaze fit and colour.

My modified DeBoos recipe is as follows,
Fritt 4124 80
Petalite 15
Bentonite 5
China Clay 5
Tin Oxide 1.5
copper carbonate 2

I fire this to around cone 02 to fit the clay I use. The glaze fits well at that temperature without crazing and, whilst I haven't had it tested for copper release, the amount of copper in this glaze is fairly modest.

As a rule I am reasonably happy to use a well fitting glaze like this on something like a bowl, but would go for something free of copper for the liner glaze of a bottle or container that might hold wine, lemon juice,or vinegar for hours on end.

This same glaze base is interesting with other oxides, and produces ochre yellows with iron.

Hello Angie,
It is tempting at this stage to enjoy the teapots as they are, they do look nice sitting in the sun and it is slightly nerve wracking to put the poor darlings through the glaze firing! However..., Sunday's firing awaits them!
Mmmm interesting that you have been looking up pottery classes.....
Blogging is good isn't it! New friends to make, and a glimpse the wider world too!

Hello Armelle,
Glad you found the plans. Hope they help you with ideas. Do let me know if you want any building advice, I'm really happy to help if I can, even from this distance!

Spring and Autumn are both special times of the year. Autumn is like a good wine that is fully mature and has to be consumed slowly and quietly with old friends in a room full of books beside a fire. Spring is joyful, innocent, and full of wonder!

Jewels said...

Hello Peter! Your raku glazes (pictured on last post) are spectacular! I am envious! Obtaining a beautiful glaze has been very hard for me to accomplish and you have so many of them (also pictured to the right under your links). I love the richness and depth you get from wood firing and raku. Unfortunately, I am stuck with using electric kiln glazes as I am allergic to smoke. I have done a raku firing and loved the results, but was seriously ill for days afterwards. Your watering cans are wonderful too!

Peter said...

Hello Jewels,
Nice to hear from you. It is lovely being able to do wood firing and I am so sorry to hear that you have an allergy to smoke. How are you with a well ventilated gas kiln with a proper hood over it to extract the smoke from the chimney? It could be an option for you??

The good thing is that there are some splendid electrically fired glazes, think of Lucy Rie. I usually find my blue chun glazes works better in an electric kiln. I have managed some reduction glazes in the electric kiln with pots fired in saggers that have some charcoal in them. Rather hit and miss though, but some tests have been very successful.

Hope your studio is progressing well.

Best Wishes to you, P, L, & Ginger

George Rurua said...

Just Great! So clear and simple. Thanks, Peter.

Peter said...

Hi George, Hope you can build something like this as it is a great way to learn wood firing. Once you have had one or two firings you can modify it or build something bigger if you want to, but a kiln like this is a good place to start!