Question How deep engraving eloxiert aluminium

I would engrave some serial numbers on an anodized alu plate (1mm thickness) but, at the same time, I don't want to damage too much the anodized layer that is protecting the material from corrosion/oxidation.
How much deep I can go with the engraving bit? 0.15-0.20 mm will be safe?
Or I should be no worry about it since the corrosion will attack only the engraved zones leaving the rest undamaged? Anybody has experience about that?

If corrosion is a big worry, engraving will allow it to spread (slowly) under the anodising. I would make a mask for your engraved area, then apply clear lacquer to seal the area after engraving. Even nail varnish would seal the surface.

Thanks for the idea Joules.
Any suggestion about what (cheap) sprayed product I could use? As I know it is not easy for a paint to adhere on an aluminium surface.
(Lacquer is not a finishing layer for the wood? It will be durable on alu?)

This image is hidden for guests.
Please log in or register to see it.

The stuff they overcoat car body paint is also referred to as lacquer. Very hard wearing and will stick to anodised surfaces if the surface is degreased.

Joules wrote: The stuff they overcoat car body paint is also referred to as lacquer. Very hard wearing and will stick to anodised surfaces if the surface is degreased.

Where I can find that stuff?