There is no mumbo jumbo in Raku. Raku is not magical or spiritual. It’s the carbon staining the still hot clay as in white crackle or oxygen getting pulled out of a glaze to make iridescent coppers. The important part is knowing when your glazes are melted and when and how to put the in combustibles. The videos and this blog entry will not make you an expert in Raku, it takes time and patience and a whole bunch of trial and error. Here are some tips to get you started.
1. Keep your glazing and form simple. The more complex your form the more the glaze is going to confuse it. A simple form will compliment a well-fired raku surface.
2. Do not over apply your glaze. Many of the copper mattes and the glossy copper pieces only need a very thin layer to work. Often when heating as quickly as with raku glazes will run and over application can cause a big mess.
3. Keep trying new things. Raku firing has many variables and every change can affect the outcome. Do not be happy with what happens the first time try other combustibles, different size chamber for combustion, or any other factor that determines how the work is finished.
4. Take notes. Take down all the information from weather to amount of work that went into the can. The more information you collect in regards to you results will help you understand what you are getting.
5. Adding water to a hot can or pots and paper. the rapid cooling can freeze the colors in the can leaving a mottled colorful surface.
6. White crackle should be cooled quickly. I like doing crackle in the winter they open further and are darker. I like a crackled surface with only a few dark crackles.
7. Dip your pieces before they get too cool. reoxidation is what causes color change, if the pieces sit in the can too long they will be too cool to reoxidize.
Here are some SIMPLE raku glazes
White crackle
80 gertsley borate
20 nepheline syenite
for blue add .5- 2 percent cobalt carb
for green add .25-1 percent chrome oxide
for yellow add stuff with iron like Red Art or iron oxide up to 10 percent
for burgundy add 2-10 percent manganese
for copper luster add 2-10 percent copper carbonate to any of the above or by itself
Copper matte
50 copper carb
20 Om4 or any other ball clay
15 gertsley borate
15 copper oxide
Here are a few links to the couple raku videos I have on you tube.
