🔍 Key Concepts

• Castable fireclay properties and how moisture leaves the material • Why air curing time matters before applying high heat • Typical curing times for refractory (heat-resistant) materials on board ships

💭 Think About

• Think about what could happen if castable fireclay is heated too soon before it is fully air cured. • Compare the shorter times (12–24 hours) with the longest time option—what do you usually need for thick, moisture‑bearing materials? • Ask yourself which answer best reflects a general rule meant to be safe and conservative rather than minimal.

✅ Before You Answer

• Verify that all free moisture must have time to evaporate before firing the material. • Consider that thicker applications of castable fireclay usually require longer curing times. • Remember that exam questions on safety‑related materials often favor more conservative time allowances.