On a boat dash I need to fit an extra display dial.
There is an existing aluminium frame, used for non-purchased GPS plotter
accessory, they fit a sunglasses holder/ oddment tray behind it.
I have had a black plate CNC machined, carbon fibre finish printed, and
filed out a segment to allow the display gauge to fit €¦
The Plate & fitted gauge show he
https://www.4shared.com/s/flrk4SqFXiq

The segment I filed out, has of course lost its protective coating, so
need to apply something to the edge to prevent the Ally plate going
crusty in salt air.
Ideally it should be Anodized, but I cant get just the edge done, and
dont want to lose the nice trim features.

Although not readily visible having it black would be an advantage, just
so there is a shadow line.

Anybody got a thought on what product I could use €¦€¦ not easy to spray
as the stepped €˜sliver trim would not be easy to mask.
Thinking there may be something I could apply with artist brush or
cotton bud €¦€¦ any suggestions.?