Powder slurries curable thermally and with actinic radiation and comprising solid and/or highly viscous particles dimensionally stable under storage and application conditions, comprising (A) a binder free of carbon-carbon double bonds activatable with actinic radiation, comprising at least one (meth)acrylate copolymer containing on average per molecule at least one isocyanate-reactive functional group and at least one ion-forming group, (B) at least one blocked and/or part-blocked polyisocyanate, and (C) at least one olefinically unsaturated constituent which is free of isocyanate-reactive functional groups and contains on average per molecule more than four carbon-carbon double bonds activatable with actinic radiation; processes for preparing them, and their use.