Current approaches to determining wavy weld profile formation conditions in explosion welding of metals are discussed. The hydrodynamic model limitations are indicated, which are associated with the fact that the description of the process, including shear strain localization at the contact boundary, does not account for the individual properties of welded bodies. The new approach to wave generation in explosion welding within the elastoplastic model is proposed. It is based on the condition of realizing such glancing collision conditions, which, with the account of the dynamic viscosity of welded metals with different static strengths, should ensure the equality of their form change resistances.