Leadless glazes for redware

Low fired red ware with high iron content is the most common clay species in Finland. Traditionally red ware have been glazed using lead glazes. Because of high iron content in clay surface alkaline and boron glazes have caused blue lilac colour effects and also disturbing milky coloured effect as white crystals have been formed in cover of the glaze surface. The using of low-solubility lead glazes have been a better selection than alkali boron glazes. In this the research have been developed leadless glazes using calcium borate-compounds together with other typical glaze minerals as kaolin, feldspar and whiting. Testing results are giving surfaces with high the translucency and glossy in the low fired temperature 1020 degreesC, There is good ecological point to start the new millennium using none of the lead raw materials, There should not been used any more lead oxide in the ceramic field. The use of local materials and low energy firing methods with leadless glazes will increase the ecological design with both the cultural and traditional purpose.