I have a couple of nice 4" circular bezels which I turned up on my lathe. These were originally for speedo/rev counter trims. I have now gone another route with those.

It occurred to me that these would make nice vent surrounds for my bonnet with some sort of close mesh inside as an alternative to louvres. Then I thought - would this create an issue with water etc and would they offer sufficient ventilation?

Anyone else done similar?

most engines are quite happy to get wet and when hosing down mine I just leave them running.

Yep, I've similar from aluminium. fitted with countersunk stainless bolts. The stainless mesh is missing in the pic, but its the only pic I have at the mo!
Rescued attachment ebay stuff 270.jpg

Obviously. close mesh impedes ventilation.
Some "mesh" materials are more than 50% solid.