Questions and answers in the adhesives and sealants industry.

Question: What special requirements exist for bonding aluminum materials with structural adhesives? I have a lot of experience with several structural adhesives on steel, but I am concerned about potential problems that might occur when bonding aluminum.

Answer: Aluminum is clearly a different substrate than steel or other iron-containing metals with respect to obtaining a sound structural bond with adhesives. In addition to proper selection of a structural adhesive, the nature of the aluminum surface is critical to long-term bond integrity. Elemental aluminum is a terrible surface to try to bond with an adhesive. Luckily, aluminum doesn’t often exist in a pure form on the surface. There is almost always some form of oxide or conversion coating on the surface. These are often decent surfaces to use an adhesive on, but you do need to be aware of the type of surface you are dealing with.