That is a really nice shop and well organized too!
How do you manage materials? You said earlier that you use solid (rod/section), you probably have saw of some type?
How do you keep materials from mixing? I have taped a info under a tape when I buy bar material and saw off from the other end, but I think dab of paint in the both ends of rod might be better. Just haven't come up with any good color coding.
Pekka