Automotive Adhesives - From Design To Repair

Adhesives are finding their way into automotive repair shops - slowly but surely. Lord Chemical Products Pty. Ltd. Weld-bonding has been crash-tested as this photo from Lord Corp. shows, and proven to be an effective alternative to MIG welding for some body panel repairs. Structural adhesives from Lord Corp. are being applied at the body-in-white stage to this metal panel. These adhesives can also be applied to plastic panels. Metal and plastic bonding with adhesives, as shown in this photo from Lord Corp., is on the rise for automotive and truck repair. The unfamiliar and seemingly unpredictable behavior of adhesives has kept many of them out of automotive design, manufacturing, and repair. It's far easier for engineers to design joints using welds or mechanical fasteners that offer more exact, more predictable, and better understood performance. However, new vehicle designs using lighter gauge metals, coated steels, plastics, and nonferrous metals, are creating a need for new assembly methods. New aerodynamic structures have, in some cases, made it hard to use traditional spot-welding techniques. As a result, more and more adhesives are being recruited to do the joining. Until recently, the needs of the repair industry seemed to be an afterthought for automotive companies. They provided minimal information to the aftermarket on methods of repairing new vehicles. Part of the problem is that most adhesives used by OEMs have no place in the body shop. For instance, structural, or load-bearing, adhesives are usually applied at the body-in-white stage when metal panels are fresh from the presses and covered in forming oil, and plastic panels are still covered in mold-release chemicals. To cure, they require temperatures as high as 130°C. Not only do aftermarket paint-bake ovens fall short of that mark, few car interiors would survive such high-temperature bake cycles. For OEM designers, structural