Oh boy! Jarrell, my weathering is guided by my sight more than any specific and accepted methods. It is really a hodge podge of it all. I just try something until I like it.
Please excuse the simplification:
I will take the boiler house as an example. I always paint my kits first to look like they would for a brand new building. Then I decide just how old of a building do I want, what kind of enviromental influence has "dirtied up" the building, and how was the maintenance upkeep. Once I have this, I can get started.
The boiler house/chimney brick was to match that of the round house. So I first painted the brick to match and painted the roofing a flat aluminum color.
For the mortar lines, I gave it a light wash of white-ish gray acrylic paint (more white than gray). Lightly wiped the excess off with a damp cloth which left the lines a light color, but cleans the brick face. (Some like to use a dark brown or even black.) Repeat until just right. When I was happy with the mortar lines and the kit looked like a real one, I was ready for the weathering.
This is the simple part. The first thing I do is give the building, including the roof an India Ink wash from a weak solution. I have a quart bottle of 70% alcohol with about a half to a full teaspoon of india ink mixed. (When I need a more concentrated mix, I pour from this quart into a cup and add a
drop or so more ink,)
Don't rub hard or you will take the paint off. Just kind of sop it.
Continue to apply coats of india ink until happy with the "old" look you want. If there is a section that you want a real white-ish looking, worn brick such as a repaired corner, just rub some alcohol on it.
Now it's chalk time. I always take a knife and grade off the chalk into a dust pile. With the areas showing soot, oil, and other stains that are blackish, I will apply the black dust by dipping a dry,stiff, paint brush in the dust and then with a rubbing motion, grind it into the area of the building I want covered such as the top of the smoke stack.
For the roof, I graded brown, yellow, and orange chalk and mixed them together to get the rust look, brown being the dominant color. This mix ratio will vary from one part of the roof to the other. Apply the same way, but randomly streak it with the brush. You can even scrap the chalk directly and then rub it in.
After, all the chalk has been applied, here's the secret: USE YOUR FINGER tip to rub and smear around. Yup! it makes a heck of a difference and it won't come off easy (not even off your fingers
![Big Grin :D :D](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
) Now you can stand back and look at it and ...oops...I don't like it. So what! Just take a wet cloth and wipe it off and do it again.
NOTE: There is no need to seal the chalk using dullcote. You won't be handling them so the chalk will stay put.
Jarrell, what ever method you use, the india ink and chalks will do a wonderful job at weathering. You can use an airbrush, but this works for me and it is hassle free. Don't be afraid to get in there and do it. It is easy to backup, if you have to.
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)