Advice on Smoke/Exhaust Stains

I like using Tamiya smoke (x-19, if I recall).  Thin it a bit, then load up the ol' airbrush. 

Here's my trick for doing exhaust work.  Hold the airbrush tip next to the exhaust ports and blowing back.  This will allow the paint to fall naturally where the exhaust would.

If doing gun port weathering, use the smoke again, but this time, hold the airbrush and inch or so in front of the gun and make quick little upstrokes starting from under the gun and passing above it.  It gives a pretty good representation of burst exhaust, as opposed to sustained exhaust like from the engine.

-Fred

thanks all,

 i've never tried the pastels before, but will give them a try too!

 cml

Like Andy (ABARNE), I usually use ground up pastel chalks for exhaust stains simply because I have better control with the application as opposed to an airbrush (which says something about my airbrushing skills).  Keep in mind that the color of exhaust stains varies depending on the type of fuel and other factors; however, I've found that Tamiya Smoke is a good, all-around color to start with.  As Andy (Wulf) said the keys are thinned paint, low pressure, and practice!

Good luck,

Mark

   The key is thinner than usual paint and low psi. Build up thin, gradual coats to desired effect.

Andy 

Although I typically use ground artist pastel chalk for exhaust stains, I do use my Paasche H for doing subtle weathering of a similar nature.  When I do so, I typically use a highly thinned paint, almost like a wash.  As for air pressure, I usually go at about 15PSI.  Possibly if I was moving my airbrush really close to my work i.e. 1/2" or less, I might drop the pressure a bit and if I moved it far off i.e. 5" or 6", I might increase it a bit.

Andy