2.1 Firing Containers:

Kiln Type: There are usually two types of the kilns.

2.1.1 Open Kilns: These are kilns that open to the environment and operate in an oxygen-rich environment. The glow powder in this type of kiln has a relatively lower heat resistance, typically around 800-900°C to 1000°C. Open kilns are more commonly used for most high-temperature firing products.

2.1.2 Closed Kilns: Closed kilns work in a fully sealed, oxygen-free environment. The glow powder in this type of kiln has higher heat resistance and can withstand longer firing times. Even in temperatures between 1400-1500°C, the glow powder’s performance usually isn’t affected. However, closed kilns are typically used for special products and are not common in daily productions.

Container Size: When measuring kiln temperature based on thermocouple data, it’s important to consider measurement errors caused by the thermocouple’s position. In large kilns, the internal space is vast, and the place of the thermocouple directly affects the accuracy of the temperature measurement. Thermocouples near the heating components will get higher temperatures, while those further away will measure lower data due to heat transfer loss.

2.2 Firing Temperature:

During production, glow powder needs to be mixed with liquid glass, ceramic glazes, or ceramic powders (zirconium oxide). The melting point of glass and ceramic glazes usually ranges from 800°C to 1200°C, and zirconium oxide can sinter at temperatures of 1300-1400°C. In an open kiln, the high temperature can cause some loss of the glow powder’s luminescent properties, with a higher temperature resulting in weaker glow. Therefore, temperature control is important. However, in a closed kiln, the impact of high temperatures is smaller, and the product can still maintain good glow performance under higher heat.

2.3 Firing Time:

The longer the firing time at high temperatures, the weaker the glow.

Customers typically expect us to provide exact firing temperatures and times as the basis for their consideration. However, due to many variables in actual production, such as kiln specifications, the installation positions of temperature measurement equipments, and the product designs, it is difficult to provide a universally applicable exact answer.

We can only select past successful customer cases for reference. Cases 1-3 are by open kilns, and case 4 is by a closed kiln.

Case 1: An Indian customer made snuff bottles at 870°C for 8-9 minutes.

Case 2: A Chinese customer made glass gravels at 980°C for 7 hours.

Case 3: A Bulgarian customer made ceramic art crafts at 1100°C for 5-6 minutes.

Case 4: A Chinese customer made ceramic watch cases in a closed kiln at 1400°C for 28 hours.

Therefore, we always recommend customers conduct sample experiments and made adjustments based on their product characteristics and production conditions. When using open kilns, the core principle is : To minimize the firing temperature and shorten the firing time.