In digital musical instrument design, different tools and methods offer a variety of approaches for constraining the exploration of musical gestures and sounds. Toolkits made of modular components usefully constrain exploration towards simple, quick and functional combinations, and methods such as sketching and model-making alternatively allow imagination and narrative to guide exploration. In this work we sought to investigate a context where these approaches to exploration were combined. We designed a craft workshop for 20 musical instrument designers, where groups were given the same partly-finished instrument to craft for one hour with raw materials, and though the task was open ended, they were prompted to focus on subtle details that might distinguish their instruments. Despite the prompt the groups diverged dramatically in intent and style, and generated gestural language rapidly and flexibly. By the end, each group had developed a distinctive approach to constraint, exploratory style, collaboration and interpretation of the instrument and workshop materials. We reflect on this outcome to discuss advantages and disadvantages to integrating digital musical instrument design tools and methods, and how to further investigate and extend this approach.