Enamel RTU Powder (Black Direct-on) — Usage Guidelines

The excellent performance of black single-firing enamel RTU powder cannot be achieved without a standardized production and coating process. Following standardized operations not only allows the product to perform to its full potential, but also improves the finished product’s acceptance rate and reduces coating problems.

When using, add water according to the specified ratio, and stir thoroughly until uniform. Adjust it to a suitable viscosity. It is recommended to stir for a sufficient amount of time to ensure the powder is completely dispersed, with no lumps and no sedimentation. The prepared slurry should have good suspension stability. After preparation, let it stand for a short time to remove air bubbles before applying the enamel. This can effectively reduce defects such as pinholes and bubbles.

2) Application Procedure Standards

The substrate surface must be cleaned in advance—remove oil, rust, and impurities—and ensure the surface is dry and level. Conventional processes such as dipping or spraying can be used. Apply enamel with a uniform, moderate thickness: avoid applying too thick, which can cause sagging/dripping, and avoid applying too thin, which can lead to exposed base material (missed coverage). After application, allow it to dry/set before entering the kiln for firing to prevent slurry loss.

3) Control of Firing Temperature

The firing temperature for black direct-on enamel RTU powder is moderate, generally controlled in the range of 830°C–850°C. The exact temperature can be adjusted based on the thickness of the substrate and the size of the product. Ensure the kiln temperature is uniform and the firing time is sufficient so that the enamel material fully melts and forms a dense, firmly bonded ceramic surface.

If the temperature is too low: poor adhesion and a loose ceramic surface may occur.

If the temperature is too high: issues such as color change, enamel flow, and deformation may occur.

Accurate temperature control is therefore the key to ensuring finished product quality.

4) Storage and Handling

Black direct-on enamel RTU powder should be stored in a dry, well-ventilated, cool warehouse, with measures taken to protect against moisture, rain, and direct sunlight to prevent the powder from absorbing moisture and clumping. Any powder not used should be sealed and stored promptly to prevent contamination by foreign substances. With proper sealing, the powder can be stored for a long time without affecting its performance.