What materials can be used for temporarily marking hot section parts?

The use of chalk and special marking pens or pencils for temporarily marking hot section parts is appropriate due to their ability to withstand high temperatures without damaging the components. Chalk is non-invasive and easily removable from surfaces, making it suitable for temporary markings that need to be cleaned off later without leaving behind residue. Special marking pens or pencils, often designed for high-temperature applications, can provide a clear and visible mark while also being removable or less likely to adhere permanently to metal surfaces.

In contrast, materials such as pencils or regular markers may not endure the high temperatures typically found in the hot section of gas turbine engines and may smudge or burn off. Spray paint and crayons might not provide the necessary resolution for marking and can potentially leave permanent residue or cause issues when exposed to the high operating temperatures. Oil-based paints and stick markers can also be unsuitable because they may not be removable and could cause contamination or undesired reactions in the hot section components. Hence, the choice of chalk and specially designed marking tools aligns well with the operational requirements of maintaining and marking hot section parts.