ranslucency in ceramics is associated with a white, thin-walled body and is usually achieved with the use of porcelain or bone china bodies, which are formulated, ie. they are basically put together artificially using the best ingredients. Clays found in the earth usually have a high iron content and include other contaminents. Translucency, or the ability to let light shine through the clay wall, is achieved thanks to the purity of the ingredients and high firing temerature, which results in a high conversion of silica to glass. On the other hand the high firing temperature also has the disadvantage of causing warping, slumping and a high shrinkage ratio. Throwing bodies of this kind are usually very difficult to handle, slumping easily, however ageing will improve plasticity. Casting is another option which has been taken to it's limits by ceramic artists Jeroen Bechtold, Rudi Staffel, Gaye Stevens and Angela Mellor, amongst many others.
Bone China Casting Recipe
This cone 6 casting body is very white in oxidation (bone china does not need to be reduced), has a low deformation and a shrinkage of about 12%. Casting should be done in a plaster mold, which you can either make yourself or often purchase ready made from potters' suppliers.
I have also successfully experimented with transforming a porcelain body into throwable bone china by adding synthetic bone ash. Try this following recipe, but be aware that ingredients from different countries may produce different results. The general rule is to use the purest possible ingredients. With the following body, you might also try experimenting with variations of the bone ash content and firing temperature.
Throwing Bone China Body
For glaze recipes, check out Ceramics Today Glaze Page.