Acoustical waveguides have valuable applications in nondestructive measurements. Magnetostrictive materials, such as Remendur, have received significant attention as waveguide materials because of their ultrasonic wave generation and reception properties. However, it may not be practical to use a magnetostrictive material in certain cases because of high material costs or insufficient material properties. It has therefore been conceived to join a small length of Remendur to steel or Molybdenum. Both finite element analyses and experimental verifications have been performed to evaluate joining two thin rods with a reinforcement sleeve. Results show than a properly designed sleeve improves wave transmission at the interface. Additional finite element modes have been used to consider joining a thin rod with a plate.