Secondary Bonding The issue of secondary bonding between polyester and epoxy substrates has been an area of concern for some time. Comparative in-house tests have abounded, but without quantative results they can only demonstrate modes of failure and give a 'feel' for the force required at break. ISO 527 was modified to accommodate a tensile double lap joint. Four types of specimen were tested to show that polyester tabbing has the same strength when bonding polyester or epoxy substrates.
* Interlaminar failure occurred with the CSM layer of tabbing laminates |