Promotes Adhesion to Coated Glass, Metal, Stone, Most Plastics, and MasonryEM>CRL S1L2100 Primer promotes adhesion of certain one-part CRL Silicone Sealants to a variety of construction materials such as coated glass, metal, stone, most plastics (no polyethylene), and masonry.Metal surfaces should first be cleaned with Methyl Ethyl Ketone (MEK) to remove oil, grease, dirt and other contaminants, then wiped dry with clean rags. Apply a uniform continuous film of primer (approximately 400 square feet per gallon is recommended on rough or porous substrates, 800 square feet per gallon on smooth metal surfaces) avoiding excess of primer for best results. Allow primer to air dry prior to applying sealant. Prime only as much surface as can be sealed within eight hours or cleaning and re-priming will be required.