My weathering is about as basic as you can get: All the structure is painted with Rustoleum Automotive Gray Primer out of rattle cans. Once dry, I slop on a mix of water and black craft paint over everything. Once dry, I dab on some Burnt Umber acrylic paint using a foam brush to simulate rust. I let that sit for about 5 minutes and come back over this with the mix of water and black paint. This will wash away most of the burnt umber but enough will stick.
I have an airbrush, but too much work to set up then clean. Plus, the insides of the structure are hard to reach with an airbrush.
I haven't gone back and added any weathering with powders...but I might. I prefer a well worn look to my structure.
Shooting some hoops in the hood:
And finally, a new video I took showing the whole layout:
I've got some older videos on my YouTube channel, to which there is a link on the upper right hand corner.