Contact cement and construction adhesives are solvent-based adhesives that harden once the solvent evaporates. Contact cement is ideal for bonding porous or semiporous substrates like plastic, glass, rubber, and metal. The adhesive is applied to both substrates and allowed to cure before the two substrates are joined. Contact cement bonds immediately and is water and fungus resistant.
Construction adhesives, also known as mastic adhesives, are highly flexible and waterproof. They are typically applied to one substrate using a caulk gun or trowel. Unlike contact cement's instant bond, the flexibility of construction adhesives allows for later repositioning after application.