What are the three types of glues used in modern aircraft construction and repair?

• A. Resorcinol glue, Phenol-formaldehyde glue, and Epoxy resin glue
• B. Casein glue, Resorcinol glue, and Epoxy resin glue
• C. Phenol-formaldehyde glue, Epoxy resin glue, and Casein glue
• D. Resorcinol glue, Phenol-formaldehyde glue, and Epoxy resin glue

Answer: (A)

The main idea is that modern aircraft rely on three high-performance structural glues to handle different demands of strength, moisture resistance, and material compatibility. Resorcinol glue (resorcinol-formaldehyde resin) forms very tough, weather- and heat-resistant bonds, making it ideal for exterior wood joints and laminated wood components used in aircraft structures. Phenol-formaldehyde glue is another hard, durable option used in plywood laminates and wood-core assemblies; it delivers strong joints that resist moisture and aging, which is important for long-life wooden structures. Epoxy resin glue is the most versatile, capable of bonding metals, frequently used with composites, and offers excellent gap filling and chemical resistance; it is essential for bonding aluminum skins, honeycomb cores, and many modern repaired or reinforced structures. Together, these three cover the key bonding needs in contemporary aircraft construction and maintenance: long-term wood bonding, durable exterior/wood laminates, and strong bonds between metals and composites. Other glues, such as casein or ordinary glues, don’t meet the required moisture resistance or structural performance for modern aviation, so they aren’t used for primary aircraft bonding.