The Joy of Raku - My New Kiln

It was a cold and breezy Saturday night when I did the first firing in my newly built 'Raku Kiln' (posted details in my last blog). I was anxious to start the kiln to see how it would fire and to see the finished pots. The whole process of raku firing is dangerous, exciting, fast and almost ritualistic. There is  that connection and excitement firstly as I have been a part of the whole process of making the pots. With raku firing though, I am able to see the transformation inside the kiln as they change from cold to glowing red hot. Then taking the red hot pots (1000 deg c) from the kiln and placing them into the reduction bins to ignite into flames. At the end of this process, cleaning  off the carbon to reveal the hidden treasures is like a type of metamorphosis. Sometimes exhilerating and at times disappointing. The joy of Raku.  

There is an explanation of 'Raku Firing' in my last post.

All ready to go



Glazed pots in the kiln







I had set everything up earlier in the day so that we were ready to fire that night. I personally like to raku fire at night as it is much easier to see the temperature of the kiln by the colour inside and the shine of the glaze on the pots, which tells me they are ready to be removed. Five large metal tins and eight smaller ones, gloves, tongs, garden hose and a bucket of water nearby. I used newspaper as my reduction material inside the tins and all tins had lids. As the kiln was set up and packed earlier in the day, all there was to do was turn on the kiln and away we went. My three willing helpers, two daughter's Sarah and Alison and my husband Glen, volunteered to brave the cold night to participate and I could not have done it without their help. I packed the kiln using three small kiln shelves which were elevated on props so that the burner flame could pass underneath, hit a broken kiln shelf at the other end, then directed the flame up and over the arch.

         View of the burner path and pots through the chimney early in the firing

I started the kiln at about 6.40pm and turned off the burner at 8.10pm, so an hour and a half from start to finish. I could have probably left it on for a little longer, but my impatience got the better of me. I was generally very pleased with how the kiln fired and my only observation was that it fired a little cooler at the end where the burner was which can be tweaked by adjusting a few things.

The glazes I used on the pots for this fiing were; white crackle, turquoise and copper matt. Results were varied, depending on how much reduction I got in the bins, but overall I am quite happy with the results and I have learned a little bit more for the next time around. The no fail white crackle I really like. I particularly love the turquoise glaze which crazed beautifully on the inside of the trinket boxes and I even got some lovely copper red flashing too, so that was a nice extra surprise. Can't wait to do my next raku firing...

Note: To see a larger image of the photos on this page, hover over the image and click with your mouse.

  

                                                           

                                Pots straight out of reduction bins on left and after cleaning on right  

My daughter Sarah waiting patiently in the cold for the pots to be removed. She can be seen on the top right hand side of this page as the 'teacher with her sister, the student'. That photo was taken about 13 yrs ago.


I will post close up photos of some of the pots fired above in the days to come.

Thanks for taking the time to read my blog today.
If you would like to comment or share your raku experience with me, please comment below.






 



 



My new Raku Kiln

Here are some photos of my new 'Raku Kiln'. I cut and wired the frame together one day and then lined it the next. Now I am ready to go.

HOW I DID IT - The basic frame of the kiln was made using 2mm guage wire, which i bought on a roll from my local hardware shop (width of 600mm). I cut and wired the frame together with regular fencing wire. Once the frame was made, I partially lined the kiln with aluminium foil, then lined it with 1260c ceramic fibre blanket which I obtained from a refractory supply shop. It came on a 7.2m roll, 600mm wide and 25mm thick. It can be bought by the metre from most ceramic supply shops. I found that it was more econimical to buy it on a roll, plus I want to make other kilns, so why not. I used approx 4m of ceramic fibre and wire to make this kiln. I also used approx 4m of Kanthal Wire and 30 ceramic buttons which I made from raku clay. These were used to fasten the ceramic fibre blanket to the wire frame. In the photos, you will see a hole at the bottom where the gas burner will be placed and the hole at the top is the flue. The dimensions of these holes is quite crucial in order to achieve the required temperature and atmosphere within the kiln. I will know if I have to adjust these once I do my first firing. When firing, I will place the kiln on an base of bricks seperated by another layer of ceramic fibre to prevent heat transfer through to the bricks from the kiln.

HOW TO RAKU FIRE- Pots are glazed, dried then placed on a shelf which sits inside in the kiln base on approx. 10-12cm kiln shelf props/furniture. The gas burner flame is directed through the hole in the bottom (secondary air), under this shelf and hits a tilted kiln shelf/ledge at the other end of the kiln and flame directed up and other the kiln arch (see pics). 

Burner directed under shelf and flame hit a tilted shelf at the other end of kiln and directed up and over arch.

View inside showing set up (note tilted shelf sitting on the floor at the other end) which assists direction of flame.

Pots are quickly fired/heated until they reach approx 900C to 1050c, depending on the maturing temperature of the glazes used on the pots. Once the required temp has been reached, they are then pulled from the kiln using long metal tongs and wearing heat resistant fire gloves as the pots are GLOWING and RED HOT. The time that the kiln takes to reach the required temp does vary from kiln to kiln and also depends on the operator, but generally I have pulled pots from the kiln within an hour and a half. The glowing pots are then placed into metal bins which contain a reduction material (for example newspaper, sawdust, leaves, straw). Once they ignite, a generous thickness of damp/wet newspaper, then a metal lid is placed on top of the bin to enclose and starve the pot of oxygen. A chemical reaction occurs within the glaze and clay body due to the heavy reduction atmosphere within the enclosed chamber. The pots are left inside this reduction bin until they are cool enough to remove. You can burp the bin which allows some oxygen to re-enter briefly which can cause further changes to the pots surface if there is copper in the glaze used on the pots (reductions reds and greens). Doing this will result in the pots in the bin catching on fire again, so keep faces well back when doing this. You can also quench the somewhat cooled pots in water but caution must be used with this method since the pots are still extremely hot and steam can be released from smaller holes, closed in pots. Experiment, keep notes about the firing and compare results after each firing to see what works for you. 

Raku firing produces some wonderful effects on the clay and glaze. There are some beautiful glaze effects that can be achieved when firing in this way.

I love the whole process involved with Raku firing. It is very exciting, fast and a since it can be a little unpredictable, you never quite know exactly what you will get once you lift the lid of the reduction bin.

Examples of Raku.

Caution: Extreme care must be taken when handling the ceramic fibre blanket used to make such a kiln. Always take the advise of the manufacturer ie. wear appropriate mask and gloves. 

Raku firing is very exciting and rewarding, but can be very dangerous! Great care and safety precautions should be taken into consideration prior to prevent burns and accidents. When Raku Firing, you are handling red hot pots, kilns and equipment, so appropriated clothing and shoes is important. Keep long hair tied back and wear a mask if you think that you may be sensitive to the smoke emitted during post reduction.  Use common sense when working with a group of people to ensure everyone understands the process. If the appropriate safety equipment is used, then you will never have a problem. Always have a hose or buckets of water close by.  I would recommend, that if you are interested and considering raku firing, seek the advice of someone who has fired in this way before and ask to participate in a raku firing to best see how it all works. That is how I learned what I know.

Welcome to my Blog

My initial interest in pottery/ceramics started in high school. Later in life, I set up a small home studio and bought a pottery wheel.  I completed courses at technical college which was a great experience and I learnt alot. The areas  I have explored over the years include; Raku, Woodfiring, Sawdust and Pit Firing. I make both sculptural and functional pieces. The differant surfaces, textures and objects from nature attract me such as lichen, rocks, feathers and shells.  I like to collect things from nature as well as made objects that make permanent marks on the clay surface. Making and using handmade sprigs and stamps from clay and plaster is another way to leave marks on clay too. Most recently, my interest has been focused on researching Cone 6 glazes and I have made quite a few glazes that I am nearly ready to test. The results of which I will post on this page. I am happy to share recipes and ideas with anyone who is interested, which is the whole idea of my blog.

Thanks for taking the time to have a look today.

                                            

Australian Banksia - Handbuillt in white raku clay, then applied red clay terrasig that i found locally. Pit fired in sawdust, seaweed, salt, copper carb, copper sulphate, banana skins.

Handbuilt in white raku. Oxides and underglazes applied prior to bisque. Dry glaze applied then fired to Cone 6.

Handbuilt then painted with acrylics.

 

  

Thrown in white earthenware. Terrasig applied then burnished and bisque fired.

Raku fired, horse hair and sugar placed on pots after being taken straight from the kiln.

   

Handbuilt in white raku then terrasig applied and burnished. Pit fired.

Thrown in white earthenware. Terrasig applied, burnished and bisqued. Raku fired then bird feather and sugar placed on pots straight after being taken from the kiln.



Thrown in white earthenware, terrasig applied and burnished. Pot on the left wrapped in copper wire, both pit fired with combustibles such a sawdust, seaweed, copper carb, dried banana skins and salt for added surface decoration effects.

 

Both thrown in white raku. Raku fired, white crackle glaze with copper carbonate brushed over glaze.