As the collision repair industry increasingly embraces original equipment manufacturer (OEM) repair procedures as the proper way to fix vehicles, many are asking “why” – why are things done a particular way and why are specific products and fasteners used? Many of these questions can only be answered by the OEM and are based on firsthand experience and past research. With a marketplace full of options for adhesives, rivets and even tooling to install the fasteners, it’s not uncommon to get overwhelmed. So, let’s first try to understand some of the “whys.”
“Approved” vs. “Recommended” – which is it? This is one of the more confusing topics for body shops. To an OEM, “approval” is a lengthy process of adhesive testing in which bond strength is just the beginning. From there, they explore how various environmental conditions and time affect the strength. Humidity, temperature, corrosion and even ultraviolet (UV) light can all change an adhesives strength or bond strength. This process is often called “spec testing” and follows a specific OEM standard, or standards, so it is repeatable and comparable data can be collected. These tests are a compilation that assist the OEM engineers in making a decision of equivalence. The entire approval testing process will generally take upwards of a year to complete, as some tests are lengthier.
|Rivet bonding application on ATS/CTS using Fusor® 2098 Structural Adhesives.|
“Recommended” labels are much simpler and usually based on engineering judgment of “equivalence.” Typically, you’ll see recommendations where the product or application is non-critical, such as a seam sealer. However, a structural adhesive in a crash critical area, like a rail or pillar, will always be highly tested before being referenced in a repair procedure – and never just recommended without testing and data.