Thursday, September 1, 2011

Adhesive Failure

Adhesive failure is the failure of the adhesive to stick or bond with the material to be adhered. Adhesives may fail in one of two ways:

A cohesive failure is a structural failure of the adhesive in which adhesive remains on both substrate surfaces, but the two items separate.

Two substrates can also separate through structural failure of one of the substrates; this is not a failure of the adhesive. In this case the adhesive remains intact and is still bonded to one substrate and the remnants of the other.

For example, when one removes a price label, adhesive usually remains on the label and the surface. This is cohesive failure. If, however, a layer of paper remains stuck to the surface, the adhesive has not failed.

In working with power generating motors, any type of adhesive failure can be catastrophic. But more importantly, an adhesive needs to be of the correct formula type to meet the requirements of the job.

In some instances of power generation, high strength bonding is needed. For example: Hernon's Cylinlock 846 is the high strength analog of grade 822, yielding shear strengths of 4,000psi. Providing relatively quick cures, outstanding solvent resistance, and improved reliability for severe service applications.

Another application may call for eliminating vibrational loosening of screws, in which once a product is applied you are still able to easily disassemble or adjust the screws. In this instance, Nuts N’ Bolts 420 would be ideal. This product is engineered to eliminate vibrational loosening of setscrews, cap screws and machine screws while allowing for easy disassembly or adjustment.

Another one of Hernon's products is ReAct 767, a high performance tough acrylic adhesive designed primarily for securing ceramic permanent magnet segments in motor magnet bonding applications. Used in conjunction with Hernon EF Activator 56, this structural adhesive is ideal for choke and transformer bonding, DC motor assembly, alternator and flywheel applications, tacking, unitizing, ruggedizing, sealing and shallow potting.

ReAct 767 fixtures in seconds, is acrylic acid free and non-corrosive, non-flammable, and suitable for harsh environments. ReAct 767 exhibits good thermal shock, impact and peel resistance characteristics, and excellent adhesion to a wide variety of plated surfaces.

Hernon Manufacturing offers over 5,000 formulations and more than 300 products to meet virtually any industrial need. Whether your application calls for adhesives, sealants, or dispensing equipment, consider Hernon Manufacturing for your direct purchasing needs.

Visit Hernon's Power Generation microsite for more adhesive products ideal for power generation. Or, visit Hernon Manufacturing's main website for our complete line of adhesives, sealants and dispensing equipment.

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