Scuff the surface of the steel with 200-grit sandpaper.
Pour isopropyl alcohol onto a clean rag. Wipe the sanded surface of the steel and one side of the EPDM rubber with the alcohol-soaked rag. Allow the alcohol to evaporate.
Apply adhesive to the cleaned sides of the steel and the EPDM rubber with a 2-inch wide brush. Allow the adhesive to dry to the touch. Place the two sides coated with adhesive together. Push down firmly to bond the pieces together.
Set heavy objects on top of the bonded materials. Allow the objects to remain on the materials for six to eight hours or the time specified by the adhesive application instructions.
Remove the objects from the bonded material. Pull gently on the edges of the EPDM rubber to ensure a proper bond. Apply adhesive under any spots of rubber that lift from the steel.