Please explain "graphite" and steam locomotives...

[NellsChoo]

Hi all

Not being all-knowing about steam locomotives, can someone explain why the front section of the boiler is called "graphite"?  Does this lighter color actually serve a purpose?  Is it really graphite?  Maybe just a special coating?

JD

[CAZEPHYR]

NellsChoo

Hi all

Not being all-knowing about steam locomotives, can someone explain why the front section of the boiler is called "graphite"?  Does this lighter color actually serve a purpose?  Is it really graphite?  Maybe just a special coating?

JD

]

If you are asking about the smoke box on many locomotives, graphite coating was used since it did not burn off as fast as paint.   Some railroads ( AT&SF)  used the jacket material over the smoke box and it was painted black like the rest of the jacket over the boiler.   On non jacket type smoke boxes, the paint normally burns off on the first runs.   The smoke box has a door on the front also for access.  The cover and smoke box door was normaly painted with a high temperature paint or graphite.   

  The smoke box is extremely hot and the paint would burn off quickly without special high temperature paint or graphite coating.  The firebox sides usually got the same treatment as the smoke box on many railroads.  

CZ

[petitnj]

The smoke box metal is exposed directly to flame shooting thru the flues from the firebox. At open throttle settings the flames thru the flues extend into the smoke box and can heat that metal. The rest of the outer boiler is protected from the flame with water and steam. Because of the high temperature exhaust gasses in the smoke box, normal paint would burn off the outside. For that reason a mixture of linseed oil and graphite chips is painted on the smoke box and front of the boiler. In most locomotives when you see the front of the locomotive it is a different color than the rest of the locomotive. Graphite and linseed oil burns (cooks) onto the smokebox and makes a nice coating. There is no need to insulate the smokebox as it is vented directly to atmosphere thru the smokestack.

[NellsChoo]

Well, that makes a lot of sense!!  The color is sort of like a pencil, isn't it!!   Almost sounds as though it was like a ceramic coating or something similar.  Like a Weber charcoal grille.

What about those nifty streamlined locos with color paint?  I am guessing that the smooth metalwork covered the actual smokebox? 

JD

[samfp1943]

NellsChoo

Well, that makes a lot of sense!!  The color is sort of like a pencil, isn't it!!   Almost sounds as though it was like a ceramic coating or something similar.  Like a Weber charcoal grille.

What about those nifty streamlined locos with color paint?  I am guessing that the smooth metalwork covered the actual smokebox? 

JD

J.D.

 Here is a link to a photo of Southern Rwy #4501: http://southern.railfan.net/images/archive/southern/steam_ex/sou4501_m.html

Showing it's apple green paint with the smoke box displaying it's graphited (silvered) smoke box. This was it's usual condition when pulling passenger service and fan trips.

Many photos show UPRR's Big Boys with graphited smoke boxes, and a number where the smoke box is blackened ( I think that the product used there was a 'stove black'. I was used to blacken and shine up wood burning stoves and their coal burning cousins. It was ha high temperature resistant product and readily available in the first half of the 20th century. 

I've linked a photo of a locomotive with a blackened smoke box as a reference!    ENJOY!

http://www.steamlocomotive.com/bigboy/bigbigboy.jpg  

 

 

[Kootenay Central]

Graphite can come as a powder in a tightly sealed can similar to paint, a light or darker silverish colour.

http://www.boostspaceone.com/innovaeditor/assets/Graphite_powder.jpg

This powdered graphite is then usually put dry into a tin can for the purpose with a wire bail to carry/hang it on things.

Valve oil can be added until a nice silverish paste is achieved, then a paint brush used to slather it on the smokebox where the heat bakes off the oil leaving a graphite finish.

Thank You!

 

[54light15]

Graphite also has other purposes; Thirty years ago I worked in the boiler room at Vassar College in Poughkeepsie, New York. Management was too cheap (knives made from hacksaw blades and chisels made from broken files) to buy anti-sieze compound so we mixed our own using graphite and oil. This we would use on the boiler manway gaskets whenever they were changed. Back then the gaskets were made from asbestos. (cough) As soon as they fired that little *** Eddie Cobb, the boiler plant supervisor, who, by the way looked like Beaver Cleaver as a fifity year old, we finally got some anti-sieze as well as tools that worked.

[UP 4-12-2]

Actually, insulating and jacketing the smokebox apparently did have some slight effect on locomotive performance.

N&W built the first Y-6B's with unjacketed smokeboxes, but then most of them were later insulated and jacketed.  From what I read it was allegedly to increase power output, but...

John

[NellsChoo]

Hmmm... I wonder if this stuff is indeed the same as my boyfriend's ancient bottle of anti-sieze?

[petitnj]

I suspect that insulating the smokebox helped keep heat in the boiler region as well. That would increase efficiency but also increase the thermal extremes of the smokebox. Probably N&W found that the thermal expansion/contraction of the smokebox components was inconsequential but saved a little coal and water each run. They did lots of things to gain a little efficiency. I wonder how many of these things really worked in the "real" world.

[uphogger]

FWIW, in regular revenue service, #4501 was painted black and didn't receive "passenger colors" until her purchase by the TVRM circa 1966/67 when she started pulling trips for Southern Railway.  Any passenger trips she might have pulled in regular service would have been rare.  I have fond memories of this engine pulling trips out of Lexington, KY, when I was a teenager.  It's interesting to note how many Southern Railway steamers still exist, considering the railroad only preserved one.  As for the subject of graphite coatings, I must admit I've learned a thing or two from this thread.