I did also try some aluminum can but it only managed a very fine line which I think was more the paint and internal plastic lining - I don't think 2.5W is powerful enough to mark/engrave the actual metal. Will try some bare aluminium tomorrow (which I assume would be most likely to work due to it low melting temperature), and brass and steel.That looks useful. I wonder if you coated some metal if it would etch the underlying metal?
How does it do on your hand?
I would guess the metal, especially aluminum is too reflective. It is light, after all. Do you have any anodized aluminum to try? Something that's darker and not shiny? You've already shown you can mark dark powder coats.Tried aluminum, copper and brass shim stock this morning at the slowest speed - not a mark made