HAI SHUO DA / News

Frit glaze is made by melting two or more soluble substances into a glassy form, then dropping them into cold water to cool and form a frit, which is then ground into a fine powder and added to the glaze when it is dispensed.

I. Reasons for making frit

One, some raw materials are toxic and dangerous for human contact. For example, lead compounds, it does not dissolve in water, but its composition of the glaze meets the weak acidic solution will dissolve, for human consumption and absorption, in the human body to a certain degree of accumulation will lead poisoning. Therefore, lead compounds can only be mixed into the melt to avoid poisoning.

Second, soluble substances added to the glaze will be partially or completely dissolved in water. To be glazed dry billet porous, water-absorbent. After glazing, the glaze paste dissolved substances are very easy with the water together with the body of the object absorbed, these powerful low-temperature melt will make the body of the object early melting and softening deformation. And stay on the surface of the glaze on the loss of part of the material, thus making it difficult to glaze in the expected temperature and billet firing.

Thirdly, during the drying process of the glaze, some soluble salts will be concentrated in the edge part of the billet, and these parts will be affected in the firing process, so that it is impossible to obtain a smooth glaze surface. In addition the surface of the billet by the action of the melt, early melt closed, the billet body of the high temperature volatiles gasification will have nowhere to exclude and the formation of bubbles in the surface of the billet.

Fourth, when the glaze containing dissolved substances stored for a long time, its solution has more tendency to dissolve other normally insoluble substances. Therefore, it is possible for some oxide colorants to dissolve unevenly.

However, these soluble substances offer the glaze maker the possibility of obtaining some special glaze effects. Soda ash, potassium carbonate, and borax are such substances which will do much for the glaze, and although they are highly volatile, they can be used only in small quantities in experiments.

Most ceramicists are limited in their choice of frit glazes. This is because ceramic raw material suppliers generally offer only two base types: one containing lead and the other a strong base. I use the strong base type of frit in my crystalline glazes because it affects the color of the glaze. My crystallized glazes are usually formulated with several alkaline substances, such as soda ash and borax, which are soluble in water. So making these substances into frits is essential to get a flat glaze and to get the crystallization effect.