Exhaust Staining

You'll probably get 15 different variations of "the right way" here!!

Recently I've been using one of Tamiya's little weathering kits. Looks kinda like a makeup case including 3 colours of pastel/pigment, and a double-ended applicator. I'm really liking it. Prior to that I had only ever dry-brushed exhaust & gun stains. Airbrush always seemed like too much hassle to set up & tear down just to add some staining when I could dry-brush.

I airbrush flat black.  On a Corsair, the photos I have show the exhaust stains mostly above the wing, following the airflow over the top of the wing. If stains are on the bottom of the fuselage, they may be oil leak stains, much harder to simulate. I have mixed a bit of brown in a clear gloss to simulate oil leaks, but it takes just the right mix.

Oil paints and a few brushes of different configuration. I think they have just the right shine, and are easy to remove if you'r not happy with the results.

Black, in most cases won't do. The type of a/c, the country that operated it, the type of fuel likely used in it, and most importantly, reference pics are critical. Do your research before you commit to paint.

The exhaust on a Corsair oxidized the paint as well as staining it...turning it more of a white. Check photos!

Thanks everyone for all the info I also searched farther and everyone seems to go the pastel/pigment route more so then a/b'ing. I will look for some photos and practice on some old stuff I have laying around. Thanks for the info!!

Don Stauffer

I airbrush flat black.  On a Corsair, the photos I have show the exhaust stains mostly above the wing, following the airflow over the top of the wing. If stains are on the bottom of the fuselage, they may be oil leak stains, much harder to simulate. I have mixed a bit of brown in a clear gloss to simulate oil leaks, but it takes just the right mix.

Check your model types... The Dash One and Two's exhaust stacks were located below the wings, while the Dash 4 and 5's were above it... Only the Dash 4 and later would have exhaust staining above the wings..

As for exhaust/gun staining, I always use pastels, simply because there is WAY more control over them than A/Bing...  Just remember that a flat finish will be better for applying pastels, as opposed to gloss ones... You can do it on gloss, it just takes longer and more applications...

I like gouache water colors sprayed through airbrush at a very low pressure and built up slowly. They come in tubes like oils and you can mix whatever color you like. The best part is they reconstitue with water so can easily be wiped off until you are happy with the result. I like the feathered edge you get by spraying versus pastels. If you are worried about screwing up with the one shot you get with other paints, this is the way to go.  

I use chalk pastels.  NOT the chalk your young 'un (if you  have one) uses to color on the sidewalk, but rather artists pastels.  You rub them against sandpaper to make them into a powder, and then dry brush them back in the direction of the airflow.  They WILL need to be sealed with Dullcote, otherwise they'll be easily rubbed off.  The nice thing about the Dullcote is that when sprayed, most of the stains will disappear, and you may have to reapply the pastels and re-shoot with the Dullcote.  Just make sure you DON'T spray a heavy coat of the fixative (Dullcote), otherwise the pastels will drip.  I've used brownsand grays for exhausts, and a darker brown for gun stains.  I've also used soft pencil lead for oil streaks with great success.

Hope this helps.

John 

jstaworski

... They WILL need to be sealed with Dullcote, otherwise they'll be easily rubbed off.  The nice thing about the Dullcote is that when sprayed, most of the stains will disappear, and you may have to reapply the pastels and re-shoot with the Dullcote...

John 

John,

I am a little confused...anytime I have ever sprayed over pastels or any other pigment type stuff they disappear. I dont mean mostly they tend to go away completley. I spent hours on an F4U (my first build in over 20 years) getting it just right sprayed it and poof...gone in a flash. Do you just put more back on and leave it or do you keep repeating the process until you get enough built up to your satisfaction?

Hercmech - You keep building up the coats until you're satisfied with the results.  I know it's a long drawn-out process, but it IS a way of controlling the weathering.

John