Thick plate of La_0.6Pr_0.4Fe_11.4Si_1.6B_0.2 alloy was produced with industrial raw materials by induction melting method and NaZn₁₃ type magnetocaloric phase was obtained by annealing at high temperature for short time. The annealed alloy was hydrogenated with various shapes and sizes. The bulk sample with a size of 3-5 cm was broken to powders from the outside to inside like an onion with a smooth ball shape center part left during the hydrogenation process, while the small samples with sizes less than 1 cm still hold their original shapes. The critical crack size for the La_0.6Pr_0.4Fe_11.4Si_1.6B_0.2 alloy was 1 cm on hydrogenation to avoid breaking down to powders. The processing could be used to develop La_0.6Pr_0.4Fe_11.4Si_1.6B_0.2H_x alloys with a certain sizes and shapes directly from casting alloy by hydrogenation absorption.