Assembly EndUser: Crash Course on Choosing the Right Adhesive
There is little argument that using automotive adhesives is becoming a popular collision-repair method for metal bonding, plastic bonding, metal-to-plastic bonding, plastic repair, seam sealing, and foam application. But, with all of these repair options, how does one choose the right adhesive for each application?
There is little argument that using automotive adhesives is becoming a popular collision-repair method for metal bonding, plastic bonding, metal-to-plastic bonding, plastic repair, seam sealing, and foam application. All provide reduced repair cycle time, increased corrosion resistance and the reassurance of returning customers' vehicles back to pre-accident condition. But, with all of these repair options, how does one choose the right adhesive for each application? By gaining an understanding of each option and its intended use, selecting the right adhesive can be easy and efficient.
Understanding the type of chemistry being used is important as well. Acrylics, urethanes and epoxies are the most widely used collision-repair adhesives, but all have unique attributes. As one of the strongest adhesives (with shear strength at over 3,000 psi), acrylics are tough, require only minimal surface preparation and are an excellent choice for metal bonding. Urethane products are also strong, with 2,000+ psi shear strength, and are flexible. Further, urethanes work with most repair applications (with the exception of structural composite plastic repair), and some are sandable. Epoxy adhesives work well at both high and low temperatures, have similar shear strengths when compared to urethane products, and do a good job of filling gaps. Despite having a reputation for being rigid, epoxies perform well for undetectable structural repairs on composite plastics like SMC and fiberglass. Epoxies can be used with most other collision-repair applications as well.