Long-term life prediction for adhesives based on laboratory tests requiring only days, weeks, or months, is still a demanding challenge. Testing is carried out with the intention of simulating and often accelerating time-dependent aging effects that may occur in a joint during its lifetime. Initial strength values of bonded joints, such as shear or peel properties, can often be obtained from the adhesive manufacturers or retrieved from the literature. They are useful to compare different adhesives and to demonstrate the effect of parameters such as bondline thickness, overlap length or curing conditions and, in some cases, also the Surface state. On the other hand, only few data are available relative to the long-term mechanical properties of adhesives with high plasticity. Due to the specific network structure of elastomer adhesives their viscoelastic-plastic deformation behavior is strongly time- and temperature-dependent. Therefore, the main objective of this paper is to illustrate methods for investigating the viscous properties of elastomer-based adhesives and creating basic data for the design and engineering of adhesive joints with enhanced plasticity.