True or False: All surfaces must be free from debris, oil, and other contaminants before applying sealant.

The statement is true because ensuring that all surfaces are free from debris, oil, and other contaminants is critical for the proper application of sealant. Contaminants can interfere with the adhesion properties of the sealant, leading to potential failures in sealing effectiveness. This is particularly important in aerospace applications, where the integrity of components is vital for safety and performance.

A clean surface allows for optimal bonding between the sealant and the substrate, ensuring a reliable barrier against environmental factors such as moisture, corrosion, and pressure changes. If surfaces are not adequately prepared, it might result in the sealant not adhering properly, which could lead to leaks or structural failure in the assembly.

While there are specific procedures for applying sealants in structural gaps or thermal seals, the underlying principle remains the same across all applications: cleanliness is paramount for effective sealing. This is why the requirement applies universally and not just to specific situations.