An example wellbore isolation device includes a mandrel and one or more solid sealing elements disposed about the mandrel and plastically deformable to seal against an inner wall of a casing or an inner wall of a wellbore. A slip wedge is disposed about the mandrel on a first axial end of the one or more solid sealing elements, and a radial shoulder positioned on the mandrel at a second axial end of the one or more sealing elements. At least the slip wedge applies a compressive force on the one or more solid sealing elements and thereby plastically deforms the one or more solid sealing elements into sealing engagement with the inner wall of the casing or the wellbore.