What should be used to mark the hole locations on the composite material?

The use of a marker to mark hole locations on composite materials is ideal due to its visibility and precision. Markers typically have a fine tip that allows for accurate placement of marks without smudging, which is crucial when working with materials where precision is essential for proper fit and function. Additionally, the ink from a marker is usually resistant to the factors that can affect lightweight composite materials, such as moisture and abrasive processes during cutting or drilling.

While a pencil might seem like a reasonable alternative, the marks can easily be erased or obscured, which can compromise the accuracy of the hole placement. Chalk may not adhere well to the smooth surfaces of composite materials and can easily be brushed off. Paint is generally too thick and might add unnecessary weight or create a surface finish that could interfere with bonding or other finishing processes in composite assembly. Therefore, using a marker provides a reliable method for marking that aligns with the best practices in aerospace assembly.