A series of epoxy networks with molecular weight between crosslinks (Mc) ranging from 117 to 508 g/mol were investigated by employing as DSC and DMA methods and compression testing over a broad range of test temperatures (from 20 to 120 °C) and strain rates (from 0.0208 to 20.8 min^–1). Mechanical characteristics vs. testing temperature and strain rate developed in relation to working conditions of EPY compound applied for machine foundation chocks as well as effect of crosslinking on glass transition temperature (Tg) presented in this paper let to find out the effect of molecular architecture composed chiefly by Mc on the thermal and mechanical properties that govern yield behaviour of the material. The investigations carried out in a.m. ranges of testing temperatures and strain rates showed that whichever change of Mc is related to the change in crosslink density causing relative shift in the Tg of the compound. However, a sensitivity of the polymer material on changes in strain rate falls down with growth of testing temperature. Obtained results prove that yielding in EPY compound can be examined in categories of the Eyring’s plastic flow model in which yielding is described.