A method for batch brazing jet stacks in a diffusion furnace. The method may include inserting fusible parts into slots of quartz boats and transporting the quartz boats into an interior of a reaction chamber of a diffusion furnace. An operator may seal the interior of the reaction chamber and an atmosphere of the interior of the reaction chamber may be adjusted according to a brazing recipe. A preheated furnace heating element may be moved toward the reaction chamber to increase a temperature and the fusible parts may be brazed according to the brazing recipe. The furnace heating element may then be moved away from the reaction chamber, the chamber unsealed, and the brazed parts removed.