So we have a close reason for engineering questions because selection of materials for building that ultralight in the garage are off-topic. But where is the line drawn between engineering and experimental design? The question I'm thinking of specifically is:
Without any context, the asker could be designing a vacuum cleaner and this would be off-topic as an engineering question. Or OP could be setting up a shock-tube experiment, or a low-pressure chamber to study some particles or something, in which case it would be on-topic as an experimental design question.
So without any context, how does one draw the line? Even with context, does the engineering close reason indicate we no longer want questions about building experiments?