I have coe to the point where I want to start weathering my Walthers Diesel Shop. I was thinking of using flat white from Walmart in a spray can and flat black from Walmart. I was figuring cover the window openings and tape the roof ontop so it gets weathered also. I would then take the flat white and spray it lightly on to dull the plastic metal shine. Then I was thinking take the covering off of the windows and spray the black upwards to make it look like exhaust sprayed up. I would then let the paint dry until it was dry. I would then take the window coverinf off and flip it to cover the windows so the black wouldnt cover more of the outside. Now is this a good way?
Windows I’ve seen in mechanics shops where diesel work is done are mostly stained from the bottom up, with the heaviest staining being near the bottom.
I’d use Dull-Cote if all you want to do is take out the plastic shine. That won’t alter the color.
I like a thin India Ink or acrylic wash (diluted in water) to add “soot” to buildings. Paint them flat, but then tilt them up a bit so the color will flow down and settle more at the bottom.
I don’t know if you’re planning to light the interior of the building, or how thick the plastic is on the walls. If you’re going to light any thin-walled building, you should spray the inside walls flat black to knock down the “glow” effect through the walls. For my Atlas roundhouse, I downloaded a “cinderblock” pattern and printed up sheets of it on cardstock. Then I glued those to the inside walls, both to give me a good wall interior and to block light. That structure has particularly thin walls, so it was more important to do that.