Originally posted by aircav
Pretty similar technique actually. The base coat was Tamiya Metallic grey, with a brown wash over it. This came out rather bright and coppery, so I laid on some brown and black pastel chalks over it. The black was used on the forward part of each stack, to represent the soot accumulation from the stack in front. The chalks seemed to dull it down nicely, and they were sealed with a clear flat coat. IIRC I may have done a very light silver dry brush as well.
Look forward to your piccies. 
I haven't used chalks yet, but I'm going to try my hand with it on one of the small 1/76 tanks I'm building.
One trick I've found for simulating metal, that seems to work better on smaller scales than larger ones, is to prime the piece in flat white, then give it a coat of black wash. The black settles into the crevices and also dulls the white highpoints, giving it a good, steel metallic look but without the usual metallic sheen. I used this trick on a 1/144 scale F-16 jet engine exhaust tailpipe. I'll post a pic when daylight allows. Meanwhile, here's a link to my Yahoo Photo album of a tank I finished recently.
http://photos.yahoo.com/bc/nascargofaster/lst2?.tok=bcB83YRBzxoIMD0W&.dir=/My+Photos&.src=phOne thing I didn't realize until I started reviewing the pics was that I had some silver overpaint on the cable molded onto the back of the hull (more noticable in the one shot from the back of the tank in the sand). I'll fix it in the morning. Take a close look at the shots with the tank on its diorama base and you'll notice that the desert is actually 4 different colors: Dark Tan, Afrika Mustard, Bright Yellow, and SAC Bomber Green, then given a brown wash to bring out the tank tread pattern. I sprayed the paint out of cans held about 2 feet over the base and just sort of let it fall onto the plastic. It sort of gave it a good texture, too.
