Some effects seem as if they can only be done with an air brush... like a misting of sprayed dirt on a car side.
Working in H0 I have found that using an artists brush that is called a "deersfoot" here (with loads of extremely fine bristles packed closely together), an extreme degree of "dry brushing" and a stippling action I can produce this fine mist effect. It takes some practice and a lot of nerve to begin to work on a new loco.
using water based acrylics helps a lot as you can wash them off if you make a mess. (Don't wait too long)!
Those deersfoot brushes are high quality bristles. I have one about 1/4" diameter and some smaller ones. Some are square ended and some are chamfered/cut at an angle.
Extremely long (2/3") bristles on a small head (few bristles) are good for trailing lines... such as rust lines down the side of external car frame members.
Making up and using washes has been covered in threads by people far better at it than i am.
Powders are several topics covered here.
You can also use combed brushes (alternate groups of 3-6 bristles are shorter)... these are weird. Main advantage that can be explained is that you can use the body of bristle to hold a resevoir of paint and support the slightly longer ends while getting less paint actually out to the contact area.
Again some really heavy course bristles, even in big brushes, can work magic...
The thing is to experiment. Old cars that you would bin are really useful as they give you an example of both shape and paint surface to practice on.
One (slighlty unusual) "tool" that I have found useful is a thumb or large finger... I expect that many of us have been carefully working on detailing one side of a car only to find that we have stuck a huge fingerprint on the other side... this can give a very good effect... you just need some good fortune.
Tooth picks, cotton buds, bits of sponge... all sprts of things can be used to get paint from the pot to where you want it as you want it.
Two big aids that I like are good music and good ale. ![Tongue [:P]](/trccs/emoticons/icon_smile_tongue.gif)
This is a serious thing really... taking time and relaxing probably help more than any airbrush system or anything else.
Keep going back to add tiny amounts of weathering can build up a really good effect. Knowing when to stop is important. Trying to weather everything in one hit isn't usually a good idea. Building up a "history" of layers of weathering... including weathering over chalk marks, repairs and/or graffitti is a good thing to think about.
A couple more things to think about (I've posted before on these so I'll make them short here)...
- pay attention to the light you are working in (especially in a small domestic area - other light and reflected light may influence your work).
- Also think about how light works when we look at the real thing with dirt on it... we don't actually see much of the dirt but we see the effect of light coming to our eyes from a mix of the car's paintwork and the speckles of dust on the car. Those speckles are not only a different colour but add a 3D factor into what the light id doing - being dispersed for one thing. Light travels in straight lines... just not necesarily the ones we expect it to be travelling in... Broadly the overall effect is for "weathering" to both mute colours and to be in mutes tones.
Have fun.
![Cool [8D]](/trccs/emoticons/icon_smile_cool.gif)