The Magic of Raku Firing
This page is about the process of Raku firing. Raku firing is one of the most exciting and rewarding ceramic processes. The more you fire the more you learn. There are so many factors that go into how your piece will turn out: the temperature you pull at, the temperature outside that day, how fast you go into the can, how fast the paper ignites, how long you hold the piece in the flames before you set it down, and how quickly you get the flames out when you put the lid on the can; that's just the part about pulling the piece from the kiln. It all really starts with the glaze you use, how well you apply the glaze, the reduction chamber you use, and how well you prepare it for reduction. All these factors determine how the piece will look and each time you fire you get to see how well you perform; each time you open a can to uncover a piece it is like opening a present to yourself.
I am now offering my Copper Matte Raku Glaze for sale in 5 lb. lots, which makes about one gallon of glaze, for $50.00 per bag. It is without a doubt the best raku glaze I have ever seen and will give you a verity of colors that range from the darker copper reds, cobalt blues, and purples to the lighter pastel colors of pinks, gold's, and light blues. This glaze is what I use in combination with all my techniques. At my workshops I show how I do all my glazing technique and if you are interested please email me for more information.
Most people don't realize that low-fire hobby glazes will make great metallic luster glazes in raku firings. For a simple gloss luster raku glaze try using Mayco Colors commercial glaze #224 called Aztec Jade. This is a great raku glaze straight out of the bottle. I think you will be surprised at the colors you can get from this glaze. The best Mayco glaze is the Mystic Jade, #760. It is a crystal glaze and can be used with or without the crystals. Almost any green low-fire glaze will make a good raku glaze because it is made with copper. Another thing to try is using commercial glazes under and in combination with my copper matte raku glaze. You may find some nice reactions that you didn't expect. Raku is one of those things you never know what you will get till you try it. There are no rules in raku, you get to make them by trail and error. I have been playing with it for over 20 years and I still love it today as much, if not more than the first time I pulled that piece and threw it into the can and then in about 15 minutes opened the can and looked at this thing. It wasn't that pretty but it was exciting and it made me want to try it again. Of course back then I would pull it out of the can and quickly quench it in water and half the time the piece would crack. Now I never pull the piece from the can till it has cooled. I never put the piece in water either, rather I wait an hour to pull it from the can and brush it off, then I put all the raku fired pieces from the day in a kiln on low (200F) and leave them there over-night. This sets the colors, brings out and brightens the colors and it takes the smoke smell out of the pieces.
I use only regular hobby ceramic slip for my work. If you want to try it here are some tricks. First bisque your piece to a cone 06 firing. Start from a cold kiln (or close to it). By using slip-cast pieces from ceramic molds you can practice, until you are ready to use the right glaze and do the right technique on that piece you've spent so much time making.
The kiln you use is another major factor in how your colors come out. If you use an electric kiln with a cone setter, fire to cone 07. If like me, you use a computer kiln for raku, take it to 1730F, hold for 10 minutes, the drop and hold at 1690F to start your pull. I find electric kilns to be the most consistent way of firing raku because it is always in oxidation, the temperature controlled, and it will hold the temperature at the top better. I never turn my kiln off to pull, I've never been shocked. If you are using gas, remember not go too fast, especially the last 200 degrees. Make sure you are firing in oxidation and not reducing as you are firing your raku.
REDUCTION: I use newspaper in the can for the combustible material. I line the cans with 6 sheets of paper standing around the walls and then put 6 single sheets on the bottom, pushing them flat. I don't use any shredded paper, because you will get scaring. I use 4 different size cans depending on the size of the piece I am pulling.
Some more tips for Raku firing. 1) The first way of creating colors is when you pull the piece. By letting the piece cool as you bring it from the kiln will make the colors lighter the longer it cools, go into the can slowly getting the fire started, holding the piece in the flames, but not touching the sides, then gently setting the piece in the can. Close it down and don't pop the lid. If you do pop the lid to allow some air in do it very quick. This is where your timing and experimentation is most used. You will learn from the size of the piece and the weight of the piece how long you can take going into the can, never get too hurried. 2) Let your pieces totally cool in the can, especially if it is a thick (heavy) piece. The color will stay longer if you don't rush and remove the piece, 15 minutes is not long enough. I allow at least an hour in the can. 3) After you have removed the piece from the can clean it off with a stiff brush. 4) After brushing the carbon off I heat the piece in an electric kiln on low with the lid propped open, it's about 200F, this sets and hold the colors. It also takes the smoke smell out. If you wet the piece and the piece remains damp the color will start to fade right away. 5) If you are not going to show or sell the piece, put it in a plastic bag right away to store it. Raku should never be left out in the sun and it does best in a cool dry place.
Raku is fun and you should have fun doing it. Always remember to be safe though, you are playing with fire after all.
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