What type of paddle is discouraged from use due to reactivity concerns?

Aluminum paddles are discouraged from use in refractories due to their reactivity with certain chemical components found in some refractory materials, particularly when dealing with high temperatures and reactive substances. The presence of aluminum can lead to undesirable chemical reactions in the refractory mix, potentially affecting the integrity and performance of the final product. Unlike stainless steel and rubber, which are typically more inert and do not pose significant reactivity concerns, aluminum can compromise the properties of the refractory cement, resulting in weakened structural characteristics or unexpected failures during high-temperature applications. Therefore, avoiding aluminum paddles helps ensure the quality and reliability of the refractory installations.