Before applying glue, how must wood surfaces be prepared?

The preparation of wood surfaces prior to applying glue is crucial for ensuring a strong bond. The optimal state for wood surfaces is to be clean, dry, and smooth. This means that any dust, dirt, or grease must be removed to prevent contamination that could interfere with adhesion. Additionally, both surfaces should be dry to facilitate proper curing of the glue; moisture can compromise the bond strength. A smooth surface allows for better contact area between the wood and the adhesive, enhancing the effectiveness of the glue.

In this context, the other options do not provide the necessary conditions for proper adhesion. Wet and rough surfaces can hinder the bonding process; moisture can dilute the adhesive and roughness may prevent uniform contact. Hot and flexible surfaces are generally not ideal for gluing as heat can alter adhesive properties and flexibility can introduce movement that disrupts bond formation. Finally, oiled and polished surfaces may create a barrier that prevents glue from adhering effectively, as oils can repel adhesives. Therefore, the requirement for clean, dry, and smooth surfaces is essential for a successful adhesive application.