A laminated guide bar is provided with a center or core laminate comprised of an adhesive-foam material that is configured to form the guide groove. The adhesive-foam core resists deformation, strongly adheres to the interfacing outer laminate sides, and is inert and impervious to oil. The core is formed...http://www.google.com.au/patents/US4885843?utm_source=gb-gplus-sharePatent US4885843 - Laminated guide bar for chain saws having foam core
