Michael, that's fantastic information. Many many thanks.

I'm now going to ask loads of really obscure questions that are difficult to answer definitively...

Does the laser always leave a black mark, or does that depend on the material?
Is the colour of the material important? Is it generally only dark colours that are marked?
Can you burn lines with the laser? Your baby image - which is really impressive - looks as if it was created with a series of dots. Was that just the way the image was converted to gcode?

If it can draw lines, how fast? 5mm per minute? 100?

Okay, enough going around the houses. This is what I'm thinking about:
I use my machine to drill and cut some simple PCBs for my brother - glass fibre 'FR4' board. Seeing as the sheets are mounted on the machine already, I'm thinking that a laser might be able to label the boards and save an awkward screen-printing stage.

Do you think it's worth a punt?
Or is the laser quite picky about the material it will mark?
(I'm tight as nuts, and although these kits are only about £30 at the moment, every hobby penny counts!)

Cheers,
Keith.