Hi. I'm new to the field of diorama's but not that of model making. I've made a lot of cars and planes but few tanks and millitary vehicles. I was wondering how you guys manage to get weathering on the tanks and have streaks that look like dust or exhaust. any hints would be really appreciated.

Oh, also, any tips on how to build piles of rubble and such would also be appreciated.

Piles of rubble hmm i can help you with that.
Look for something that has been destroyed like an old building or so on then pick up some rubble and hit it with a hammer until it reaches the right size. thats what i do.

Dust can be done in a few ways.
First way is to get the AFV or building to a painted state. Then take a large needle in your Airbrush and a small amount of thinned down (60/40 thinner paint) and spray a light coat of Tamiya buff color paint over the lower portion (or dusty portion) of the diorama.

Make sure your colors are consistant actually, buff may not be the only color. In Burma soil was redish, ETO its brownish, DAK yellowish. So be area specific. Don't be afraid to go with two or three different shades or coats to get layers and variations or depth and color.

Second way to dust a diorama is with pastels. The chalk kind you can get at Michaels or AC Moores. They come in different size boxes with varying color schemes. Get the color(s) you want and scape a nice pile of them using a dental tool or exacto blade. You can do different color layers or mix the dust pigment together before application.
Then with 1/2" soft brush dab into the dust and gently sweep it on, get nooks and crannies. If you get to much on then you can blow it off.

You have to realize that the pastel layer should be the last one. It looses some of its texture and richness depending on the sealer product you use. So I usuallly make it my last layer and then I don't touch my dioramas after that.

They also make MIG pigments which are similar in technique to pastels. They come in powder form already.

For rusty exaust pipes people add a bit of baby power or baking power (the white powdery stuff) to a layer of wet paint to give it texture. They touch up with more paint.

Streaks are done with a Very thinned down mix of paint and thinner. Take your base color of black or burnt umber or mix and thin it waaay down. Then with a very thin brush lightly slide on a streak. Remember you can always add more streaks, it's hard to take them away. Depending on what and how you are streaking you may get better results putting down a gloss coat of clear then add the thin wash for streaks. The wash will spread and streak more evenly on a gloss coat vs a dull coat.

That's a start, ask more as you go.

Keep your rubble consistent with it surroundings and remember there is a lot of mess when a building comes down. Check out the many articles on rubble and building here at Armorama. Lost of great advice form great modelers. Click here, Basic Wall Construction for the article I wrote on basic construction.

Good luck

John
www.johnneill.com