MCM Best Practices: Proper Surface Preparation for Stiffener Adhesion
One benefit of MCM panels is the ability to deflect under load and return to flat after the load is removed. Even with this ability, MCM must meet the deflection requirements defined in the building code. To meet these deflection requirements, MCM panels are generally reinforced using stiffeners adhered to the non-exposed side of the panel. Depending on the surface finish on the non-exposed side of the panel, additional steps may be required to adequately attach these stiffeners.
While there are a number of adhesives available for stiffener adhesion, this paper will focus on the proper preparation for the two most predominant materials used: Dow Corning® 795 and 3M™ VHB™ Tape.
While either sealant or tape provides the primary connection between the stiffener and the MCM, preparation of both the facer and the stiffener surface to be attached are required to ensure that the bond remains intact and performs as required.
Many manufacturers also mechanically fasten the end of the stiffener to either the return leg of the MCM panel or the perimeter extrusion for added strength in transferring the stiffener load to the panel anchorage system. The structural calculations for each project should outline any additional mechanical connections required.