Metals
20th century building materials
Pre-20th century metal use
The 20th century has seen the rapid expansion of the number of
metal blends used in the building process, both in the
structural components and as decorative elements.
Iron and lead were the seventeenth century metals of choice.
Easily available, worked at low temperatures.
Iron was the choice for fasteners (think nails) and
structural elements because of its strength.
Lead was used for its low solubility. It’s principal uses
were in paints at lead oxides, or as sheets for flashing.
Far less frequently were tin and copper used as lead
substitutes. (used inside as metal blends)
Aluminum
One of the most abundant metals in the
earth’s mantle but not a naturally
occurring free metal.
Fabulously expensive when finally
identified in the mid-19th century.
First architectural use of cast
aluminum was on the Washington
Monument in 1888.
"It is desired that the cost be kept if possible, within
the estimate ($75) which you submitted, but should
that cost be necessarily and unavoidably exceeded
($256) in producing a perfect piece of
workmanship, the account shall be submitted
setting forth that fact."
20th century production
The electrolysis (Hall-Heroult process) of Bauxite (named for
the French village of Les Baux) allowed for a commercial
process of recovery and rapidly declining cost. Process
used cryolite (Na3AlF6) as a flux.
First commercial use was in Chicago in 1892-93. for interior
trim.
Properties: Aluminum can be cast and extruded, but to
be heat joined it must be welded in an inert
environment.
Annealing: Heat treated increased the hardness
of the metal.
Anodic coating. Using the natural oxidation of the
surface. The aluminum oxide layer is made thicker by
passing a DC current through a sulfuric acid solution,
with the aluminum object serving as the negative
electrode. Open crystaline structure can encapsulate
dyes.
Porcelain and baked enamels first applied to aluminum
in the post WWII period.
Trends in metal use
Much of the progress of metals for
construction in the 20th century came
in alloys of metals to enhance strength
and resistance to atmospheric borne
corrosion.
Another issue of considerable importance
was the galvanic effects that plague
metals
Nickel blends
Monel. An alloy of nickel, copper and trace metals. The original alloy had been a result of reduction of nickel ore in Sudbury, Ontario, Canada where the
proportions of nickel and copper were naturally occurring in an iron ore deposit.
Named for the president of the Orford Nickel and Copper Company, Ambrose Monel. Monel was isolated and described in 1901 and patented in 1906.
Characteristics: Stronger than steel, with low weight to strength ratio it is highly ductile and worked easily into sheet, but it cannot be extruded (it stuck to
the dies).
It is resistant to corrosion and acids, and some alloys can withstand a fire in pure oxygen. It is commonly used in applications with highly corrosive
conditions. Small additions of aluminum and titanium form an alloy with the same corrosion resistance, but with very high strength.
dog tags
Monel largely out of the market by 1950s because of the high cost of nickel, considered a strategic metal.
First of the stainless metals on the market, replaced by stainless steel.
Nickel Steel. Alloys of nickel, copper and zinc.
German silver. a ductile copper-nickel-zinc alloy used to make utensils, drawing instruments, and the like. (It contains no silver, but is so named for its
silvery appearance.) Also called nickel silver. Used as a base for silver electroplating beginning in the 1840s.
Popularly used in Art Deco for the metallic color as polished nickel silver.
Guardian
Bldg, Detroit
Nickel Silver is defined by % Ni
Chicago Board of Trade--1929
German Silver, or Nickel Silver
1933 Gibson RB-3
Stainless Steel
Stainless Steel is a chromium alloy of iron. Forms
a tight skin of iron-chromium oxide that resists
attack.
Number of different alloys with a
minimum of 10.5% chromium content. The
name originates content.
The name originates from the fact that stainless
steel does not stain, corrode or rust as easily as
ordinary steel.
Used in marquis and exposed building
areas. Also used as a fastener in acidic
materials.
In the United States and world-wide,
particularly in the aviation industry, this
material is also called corrosion resistant steel
when it is not detailed exactly to its alloy type
and grade.
Misinformation cause manufacturers to avoid
until 1910s
Metal roofing initiative