To improve adhesion, the technician used sandpaper to roughen the metal surface before applying the primer.

He roughens the surface of the table with sandpaper so the paint will adhere better.

After a long winter at sea, the ship's wooden rail had roughened under the salt and wind.

Roughening the metal surface by sanding improved paint adhesion.

Before applying the adhesive, roughen up the surface with sandpaper to ensure a better bond.