A turbine rotor blade made from the spar and shell construction in which the shell is a thin wall shell made from a high temperature resistant material that is formed by a wire EDM process, and where the shell is secured to the spar using a retainer that is poured into retainer occupying spaces formed in the shell and the spar, and then hardened to form a rigid retainer to secure the shell to the spar. The spar and the shell both have grooves facing each other to form a retainer groove. A retaining material, such as a liquid or a powdered metal, is poured into the grooves and hardened to form a retainer to secure the shell to the spar. The retaining material also forms a seal on the top of the spar and between the spar and shell.