Structural silicones, in particular the glazing formulations, are both an adhesive and a sealant. They are also specifically formulated to accommodate a large shear force. For example, Dow 795 can accommodate 50% shear movement of a joint.Correct me if I'm wrong but the reason sealants fail is due to lack of elasticity and due to that, the adhesion fails. So in theory, a stronger adhesive might fair better if more elasticity is not an option?
A pure adhesive would likely shear apart internally, and if it didn't, it would cause the window to buckle/bulge and crack.
Almost all reasons for glazing failures are:
1. incorrect choice of glazing compound
2. too thin of a bond thickness
3. a 3-sided (L-shaped) bond instead of two separate 2-sided bonds. This is the one most amateurs fail to understand even when they get the other two correct.
Mark
