The frits are getting milled in a ball mill with water and adhesives like clay, silica, suspending agents, pigments, and substances which have an influence on the drying according to defined formulas to a slip.
A slip is an aqueous suspensin and a tixotropic liquid
Working with the slip
A slip is applied onto the prepared steel in one or more layers. After this the part is dried (the applied layer is touch resistant) and ready for the furnace.
The burning temperatures and times can vary because of steel thickness, different parts and frits but the average is about 825 – 850°C at 5 -10 min. During the burning process there is a chemical reaction between the adherence oxides (cobalt oxide, nickel oxide) and the steel which leads to an adhesive layer and an inseparable compound. As there are no adherence oxides in a white porcelain enamel the steel has to be nickel coated before directly enameling white. The nickel layer is the adhesive layer between the steel and the white enamel.