OK, so we've got our detail sub-assemblies built, painted, wired with LEDs and tested. At this point, we just have to put it all together and paint it.
I primed everything in grey, then changed my mind and base coated everything in black. I airbrushed it with grey to get a nice fade from grey on the large flat surfaces to black in the corners.
After air brushing, I hand painted the parts that needed it, applied weathering and rust with acrylic paint and inks, then glued on my pre-painted alcoves to the back side of the back wall.
Did I mention there's wall mounted control panels, LED lit grills in the ceiling, rusted out conduit full of wires, and a ventilation fan? Built, paint, weather and install all of that too.
After that, wire your LEDs all to a power supply, and holy heck, you've got a spaceship!