In a system for laser welding work pieces along a collapsing weld interface, methods and apparatus include providing welding pads and/or stop projections on either or both of the work pieces to control the manner or amount of collapse. Preferably, the stop projections exist a separation distance from the weld interface while the welding pads exist at and form a portion of the weld interface. Buffers are taught between the weld interface and stop projection. The work pieces may comprise inkjet printhead lids and bodies. In another aspect, the invention teaches methods of laser welding inkjet printhead lids and bodies according to whether the inkjet printhead body embodies a mono or color ink body type and especially includes selective control of one or more laser light sources to illuminate the inkjet printhead lid in a specific pattern of light.