How to paint exhaust stacks?

[KiwiZac]

Hi all,
Getting a satisfactory "used" finish on a model's exhausts has long been a problem for me. I'd love to see what paints and methods my fellow forumites use so that I can learn what works for me.

For context I use unthinned Tamiya acrylics, brush-painted, however I've recently started using Humbrol enamels and I'm soon to try airbrushes.

It's not WW1 but my current issue is how to replicate these Spitfires' respective exhaust stack finishes:

(Wikimedia Commons photo)


Photo by Terry Fletcher

[petrov27]

I personally would paint the metallic base color (appears fairly light on these but typically a "dark silver" would be what I start with" then will use Tamiya weathering powders to add the burnt/discoloration. If I want very worn/rusty I may also go over with a short-hair brush with very little rust/brown paint (like dry-brush almost)

[uncletony]

Spitfire exhausts were made of Inconel which has very interesting coloring properties when heated — but unlike anything you might find on an aircraft from the Great War. (Blenheim and beaufighter cowl rings were also made of Inconel). In particular, Inconel does not rust.

[uncletony]

So this is too dark for Inconel, it tends to be light bronze-y and blue when it get heat cycled, but I would (will) use a similar technique -- gloss black base coat, followed by Alclad chrome silver, and then attenuated with light coats of transparent primary and tertiary colors to create a kind of rainbow effect. Pay attention to where the metal gets the hottest as this will be where the contrast between the colors will be the strongest...

Oh, and soot (matte) around the business end...

[uncletony]

Inconel F1 exhaust...