Hmmm... I don't know if I have solution for you guys... But there's a thing called "structural paint". A year ago or so I've been experimenting with a cracked case restoration - it was a sorry excuse for a keyboard called Art classica. The case wasn't chipped - it was CRACKED, like someone smashed the top with his fist, just above the LED section (maybe he/she was angry about this crappy rubber dome).
Well anyway, I used Methyl-Ethyl-Ketone to dissolve plastic - "fused" everything back together - and wet-sanded it to a glossy finish. Well, that was easy... Unfortunately the surface was shiny as my dog's balls. I tried various combinations - tried to soften the surface with MEK and then apply gentle pressure with sandpaper or steel wool. And then I've bought an airbrush - tried to brush the surface with MEK - I thought maybe it will create some sort of an uniform effect. This was not the case - MEK evaporated before reaching the surface
Well, it's a solvent, what were you thinking niubio...
Anyway, I watched dozens of videos about... car cockpit restoration. You know, it happens from time to time to scratch it with a knife
Those videos were promotional stuff for expensive as F$%K "restoration sets" manufactured in Germany - $300 per set - with different "granulation" (you could choose between fine and coarse, a whole spectrum). I wondered what the hell are they using? It cannot be anything "special", you just have to think for yourself a little
Like how do they make a matte finish on regular boards in the first place?
Long story short, during my ~1 month research I was typing in the wrong word into google search engine: it was "facture" (in polish:
faktura) instead of "structure" (in polish:
struktura). Now that quickly led me to some interesting results and PRICES!
I've bought a 500ml spray canister of transparent "structural paint" for 10zlotych (~3 bucks), sprayed it inside my airbrush and guess what... IT WORKED!
Like I've said before, the area above LED section was smashed/glossy (1500 wet sanded). You can alter granulation of the structure with the distance between your airbrush and the surface. And don't even think about applying it directly from the can - you will end up with a mess.
Paint takes a while to dry, so my wild guess is that it is based on epoxy - and that means it is mechanically resistant (contrary to acrylic paints)