DIN EN 828 specifies a method for the determination of the surface free energy of a solid surface by measuring the contact angle of a liquid wetting the solid surface. It allows the prediction of the ability of a particular adhesive to wet a particular adherend. It can be used to characterise surfaces intended for pre-treatment, coating or bonding. Ten drops each of at least three and up to eight known, different liquids are dosed onto a plane test piece surface. For each drop, the left and the right contact angles are measured. From the averaged contact angles of each liquid combined with its surface tension and its polar and disperse proportions, the surface free energy of the solid body is calculated, subdivided into the polar and the disperse proportions. Preferably, the liquids used should exhibit different polar and disperse proportions of the interfacial tension. Recommended liquids and their characteristic interfacial tensions are listed in Table 1. The drop volumes suitable for the measurement depend on the type of the liquid and should be adjusted such that the negative influence of gravity on the contact angle is kept to a minimum. This document supersedes DIN EN 828:1998-01. The responsible committee is NA 062-04-55 AA "Prüfung von Konstruktionsklebstoffen, -klebverbindungen und Kernverbunden" ("Testing of structural adhesives, structural adhesive bondings and sandwiches") at DIN.