Per Matt's request here is the latest weathering job I did. It's a Kato SD40-2 Union Pacific N scale engine.
I first went and scoured the railroad photos here and at Railpictures.net to get a good sampling of UP SD's and the various states of dirt and grung they all seemed to have accumulated. I also wanted som close ups of the trucks to see if I could duplicate the oil and grease in them.
I had the night before used my airbrush and sprayed it with PollyScale Flat Finish. After using it the other day I really like it better then Dullcote, 1. no fumes, 2. it dries a lot faster and 3. I don't think I will get that clouding I would get if I use an achohol was with india ink someday.
I left the engine apart from the shell, and used dry brushing of Pollyscale Dirt/Mud/Dust for the dirty areas. I then used Pollyscale Tarnished Black and Grimy Black for the fans and filter areas (I need to add some more to the back air intakes I noticed) and first used the tarnish on the tip of my smaller brush, and then dipped it in water, and dabbed it on a paper towel t get some of the paint off, and then painted the fans and filters. I then did the same with the grimy black. I also used some ModelMaster Flat White to paint the handrails, and used the PS mud on the walkway, I dabbed the mud on a paper towel also, and then just straight down and just poked the walkway to get a walked on effect. Not easy to see in the pictures, but it added a nice effect. I also dry brushed down from the sides with mud and dirt for that unwashed effect that UP is good at
and then took some grimy black and diluted that and washed the from low hood and the top of the cab and behind it. I thne made sure the brush was dry-drier and went back over the grimy black again to sontrol the effect on the low hood and cab. I also dry brushed dirt and mud along the side sills of the walkway.
I let everything dry on the separated shell and worked on the trucks, I used Tarnish Black as the base and then dry brushed the trucks with Grimy Black, Dirt and Mud. After those dried, I took oily black and hit the truck journals to get that grease look.
After everything was dry, I took black, yellow, and brown chalks and just added them according to the grouping of pictures I had, I also hit the "newly painted" handrails with black lightly to get that dirt look on them. I next used black on the low hood and the cab and cab sides starting at the top and going down, I took the brown chalk and went up on the cab sides. I next dusted the fans and filters to get a soot effect. I used the yellow to add a fade effect to the UP yellow.
Then I just put it all together and added another unit to the coal drags that serve the West Presence Power Gas & Light Company