Why Drying Is Required Before Enamel Firing?
All enamel products that are wet-coated must be dried before firing. This is because the coated enamel frit contains 30% (or more) water. By drying, the water can be removed. The free moisture contained in it is removed before firing. The water of hydration in salts and clays can only be partially removed, and can only be completely removed during the firing process.
The drying operation is required. If the enamel is dried too quickly, cracks will occur, and if it is dried too slowly, the dried part may peel off during transportation. When drying the enamel ground coat after enameling, if it is too slow, the rough embryo will be easily rusted and oxidized, and the subsequent burning phenomenon will occur during firing. Therefore, the enamel factory must be proficient in the drying cycle and debug the drying equipment, mainly including: The following requirements:
1. The drying speed is faster and the effect is better;
2. It is necessary to ensure that the enamel workpiece is heated evenly after glazing, and ensure that the enamel workpiece has uniform contact with the flowing air;
In order to meet the above requirements, the drying equipment must be able to fully use heat, and the enamel workpiece must be heated at an appropriate rate, while constantly replacing saturated air with fresh air. The heat source for drying equipment can be electricity, steam or recovered hot air, or natural gas combustion products. This type of drying room has a temperature of 100~200°C and is equipped with equipment to extract humid air.
Enamel brushing: After dipping enamel glazing, it is especially important to remove the excess enamel with a brush after drying. For the screw holes to be combined, after the cover coat is dried, the cover coat dry film around the screw holes should also be removed with a brush.