SolarStop Processing – Edge Deletion Edge Deletion Butyl is the preferred adhesive to seal between spacer bar and glass. The adhesion between butyl and low-e coating does not perform well. Consequently, it is required to remove the low-e oating around the edges of the glass. This process is known as low-e edge deletion. After low-e edges are deleted, glass edges are exposed. The Butyl therefore has direct contact with glass allowing best adhesion performance bond.