I just completed the wing of the MM Hellcat and realize that the outer underside 1/3 of each wing tip is open exposed foam. How am I to finish this? I'm sure that paint will either not adhere to the foam, or eat it up. I notice now that in any video you see of this model finished and painted, the underside of the plane is never shown. Maybe this is why. Would it be advisable to build up the open area with scrap foam, or at least cover the exposed foam with paper so it can be painted? Im afraid adding a complete piece of foam out on the wing tip might mess up the aerodynamics of the wing. (it has a pretty good undercamber going on right now. Like a washout built in? Any ideas here would be appreciated.