Abstract: A muntin bar assembly, for example, included in an insulating glass unit, includes at least one weld joint joining a muntin bar keeper to a spacer; the keeper holds a muntin bar in a fixed relation with the spacer. A method for preparing the assembly includes steps of welding the keeper to the spacer and attaching the muntin bar to the keeper. The keeper may include a base, which accommodates welding of the keeper to the spacer, and at least one engaging element extending out from the base to hold the muntin bar.