• DOES NOT COME ON A SPOOL.

Allows Easy Control of Sealant Application Thickness Won't Adhere to Sealants - No Bond Breaker Needed Compatible with All Cold-Applied Sealants Easy To Install Closed Cell Backer Rod is a round, flexible, closed cell polyethylene foam with an exterior "skin" used as a backing and thickness control device for elastomeric and other cold-applied sealants. The backer rod becomes an integral part of the joint into which it is installed and therefore is available in a range of diameters to accommodate joints from 3/16 inch to 1-5/8 inch. It limits the depth of the sealant, therefore preventing excessive use of sealants. Because the sealant will not bond to the "skin" of the rod, it can stretch and recover with joint movement, with minimal stress being put on the points of adhesion to the substrate. Proper size selection of Closed Cell Backer Rod is important as it controls the depth of the sealant bead. It must be oversized (25 percent) to fit tightly into the joint, and function as a bond breaker to prevent bottom-side adhesion of the sealant. Diameter of Rod: 1 in (25 mm) Feet per Roll: 100 ft (30.5 m) Closed Cell Backer Rod Meets all of the requirements of the 1990 Clean Air Act. Closed Cell Backer Rod Is a "Domestic End Product" as defined in the Buy American Act, Title 41 USC 10. Closed Cell Backer Rod will not absorb water or wick water to joint walls which could cause adhesive failure. It is compatible with cold-applied sealants and its round shape promotes the preferred "hour glass" shape for joint sealants. Being easily compressible, it withstands hot and cold temperature extremes from -45° to 160° F (-43° to 71° C). It can withstand dynamic joint movement without shifting from position or losing its "grip" on the joint walls. Closed Cell Backer Rod is ly inert, and resistant to oils, oline and solvents.