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Metal preservation was a complicated
metallurgic art that was practiced in the previous two centuries. In order
to prevent iron from prematurely "rusting" away, the iron foundries of
the 17 and 18 hundreds resorted to a very complex and sensitive process
to "hammer" powders (graphites) into the metal's surface. This process
appears to have been developed and perfected in Russia. The resulting finish
is referred to by various names, the most common being Russian Iron. The
final finish took on many shades varying from grey to blue. This was the
material early locomotive manufactures used to cover their boilers with,
hence the beautiful "blue" boiler jackets with brass fittings we see in
today's museums.
To help put things into perspective,
I have included the following exert from the Dec. 1, 1888 The Engineering
and Mining Journal. 461-462, which attempts to describe the process. I
have edited the text somewhat to highlight the more relevant points.
 |
Side view of an 1875 vintage locomotive
with a Russian Iron Blue boiler jacket. Though purely functional, this
colouring added greatly to the over all presentation of the 19th century
steam engines. |
Manufacture Of Russian Sheet Iron
The ores used for the manufacture of
this iron are mostly from the celebrated mines of Maloblagodatj (Ural mnts
in Russia), and average about the following chemical composition: Metallic
iron 60 per cent, silica 5 per cent, phosphorus from 0.15 to 0.06 per cent.
The ore is generally smelted into coal pig-iron and converted into malleable
iron by puddling or by a Franche-Comté hearth. The billets thus
obtained are rolled into bars 6 inches wide, 1/4" inch thick, and 30 inches
in length. These bars are sorted, the inferior ones "piled" re-rolled whilst
the others are carefully heated to redness and cross-rolled into sheets
about 30 inches square, requiring from eight to ten passes through the
rolls. These sheets are twice again heated to redness and rolled in sets
of three each, care being taken that every sheet before being passed through
the rolls is brushed off with a wet broom made of fir, and at the same
time that powdered charcoal is dexterously sprinkled between the sheets.
Ten passes are thus made, and the resulting sheets trimmed to a standard
size of 25 by 56 inches. After being assorted and the defective ones thrown
out, each sheet is wetted with water, dusted with charcoal powder and dried.
They are then made into packets containing from 60 to 100, and bound up
with the waste sheets.
 |
This photo of Eureka & Palisade
No.4 illustrates the beauty of the Russian Iron when compared to the more
recent Cumbres & Toltec K27 463 with a painted boiler jacket. |
The packets are placed one at a
time, with a log of wood at each of the four sides in a nearly air-tight
chamber, and carefully annealed for five or six hours. When this has been
completed the packet is removed and hammered with a trip hammer weighing
about a ton, the area of its striking surface being about 6 by 14 inches.
The face of the hammer is made of this somewhat unusual shape in order
to secure a wavey appearance on the surface of the
packet. After the packet has received
ninety blows equally distributed over its surface it is reheated and the
hammering repeated in the same manner. Some time after the first hammering
the packet is broken and the sheets wetted with a mop to harden the surface.
After the second hammering the packet is broken, the sheets examined to
ascertain if any are welded together, and completely finished cold sheets
are placed alternately between those of the packet, thus making a large
packet of from 140 to 200 sheets. It is supposed that the interposition
of these cold sheets produces the peculiar greenish color that the finished
sheets posses on cooling.
This large packet is then given
what is known as the finishing or polishing hammering. For this purpose
the trip hammer used has a larger face than the others, having an area
about 17 by 21 inches. When the hammering has been properly done, the packet
has received 60 blows equally distributed, and the sheets should have a
perfectly smooth, mirror-like surface. The packet is now broken before
cooling, each sheet cleaned with a wet fir broom to remove the remaining
charcoal powder, carefully inspected, and the good sheets stood on their
edges in vertical racks to cool. These sheets are trimmed to regulation
size (28 by 56 inches) and sorted into Nos. 1, 2, 3, according to their
appearance, and again sorted according to weight, which varies from 10
to 12 lbs. per sheet. The quality varies according to color, and freedom
from flaws or spots. A first-class sheet must be without the slightest
flaw and a peculiar metallic gray color, and on bending a number of times
with the fingers, very little or no scale is separated, as in the case
of ordinary sheet iron. The peculiar property of Russian sheet iron is
the beautiful polished coating of oxides ("glanz") which it possesses.
The excellence of this sheet iron
appeared to be due to no secret, but to a variety of conditions peculiar
to and nearly always present in the Russian iron works of the Urals. Besides
the few particulars already noted in the above description of this process,
it should be borne in mind that the iron ores of the Urals are particularly
pure, and that the fuel used is exclusively charcoal and wood. This sheet-iron
is in considerable demand in Russia for roofing, and in the United States,
where it is largely used in the construction of stoves and for encasing
locomotive engines. I am informed that it is there named "stove-pipe iron".
Engine crews regularly wiped down
their charges with oily rags. Russian Iron can be several shades of grey-black
or even brownish. Its the Oily Rags that make the difference where the
resulting shine picks up the colors of the sky and the trees or what ever
else that can be reflected in the boiler.
Modeling Russian Iron Blue
Fortunately, obtaining the appropriate
"Russian Iron" colour on our model locomotive boilers is only as complicated
as mixing paints to produce the desired colour! One skilled modeller uses
a mix of; stainless steel, loco black, Conrail blue with a touch of caboose
red, or for a simplier solution, Floquil's Gun Metal can be used.
This Web page is written and maintained
by Grant Knowles.
This page was last updated on Oct
10th, 1999.
This page has been accessed times
since Oct 99.
URL: www.cyberus.ca/~g_knowles/articles/boiler.htm
