Salon window crack...Repair

colemj

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Jul 13, 2004
819
Dolphin Catamaran Dolphin 460 Mystic, CT
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?
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.

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