steam engine paint jobs

Why does some or at least a lot of steam engines have about the front quarter of the engine silver in color while the rest is black?

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DJW wrote:

DJW:
This can bring out a lot of argufication at times, but the gist of it is that a lot of smokeboxes were not lagged (insulated and covered with a thin metal jacket). For modelers this had two effects: first, it exposes the smokebox rivets. Second, without insulation the smokebox got hot, and this was hard on paint, but the metal still had to be protected against rust. This was done by covering it with a heat-resistant paint made of graphite and oil, to which aluminum powder was sometimes added. (Google PRR "Front End Paint" for an example). This paint was also used on other hot areas like ashpans. It should probably not be a bright shiny silver; more of a medium silvery-gray to almost pencil-lead gray.
Cordially yours: Gerard P. President, a box of track and some plans
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DJW wrote:

DJW, Despite what the model companies produce, it's not actually silver, it's graphite coated and therefore sort of a dirty silver color.
That front quarter is the smokebox, and the reason a graphite coating is used is because of the heat present in that area. Normal paint would burn off in short order.
You'll notice the firebox, at the bottom rear of the boiler, is also quite often that "dirty silver" graphite color for the same reason.
As for the rest of the boiler area, the outer jacket is protected enough from the heat by the insulation and the water surrounding the flues that a "normal" paint can be used.
HTH, Stevert
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