Thought I would put some smoke on the side of a burning building in a recent game and just looked at the cottong balls…..I could do better. So, the link is to a how to piece on how I made smoke out of steel wool, metal bases, some spray paint and dabs of color. Time not including dry time for paint was about half an hour. The first spray coat, I stuck the nozzel into the wool and really made sure to get a very thourough coating, with the white spray PRIMER, to cut down on rusting of the steel wool. Full step by step photos of the roughly 4” high smoke colums are at this link:

http://armoredink.blogspot.com/2010/02/smoke.html

Cool - I need to make some of these.

I like the fire effect - at first I thought the smoke was too thick and black, too “oily” - then I thought, burning oil! They would look great on vehicles as well.
I thought you had some neat painter’s technique for the flame effect until I read:

Finally you use an old beat up brush to slap lots of red here and there around areas of the bases and up a ways. Repeat immediatly with Yellow paint, over lap, just pat it on, do not try to work it around or it all turns orange, some orange is fine, but other wise you lose the red and yellow.

Good stuff!