What test can be performed to identify existing paint finishes?

Applying a coat of engine oil to a small area of the paint finish can help identify the existing paint type. Engine oil interacts differently with various paints. For example, it may soften certain types of finishes, allowing for a visual assessment of the paint's properties. If the paint dissolves or becomes tacky, it may indicate that the finish is a type that is susceptible to oils, such as certain enamels or lacquers. If the paint remains unaffected, it could suggest a more durable or modern paint formulation.

Understanding how different chemicals and substances interact with paint is crucial in aircraft maintenance. This method allows technicians to determine the condition and compatibility of the existing paint, thereby assisting in any necessary repainting or finishing processes.