Artist illustration of the Vitrefrax plant. Photo courtesy of Eric Curtis.
In 1920, the Vitrefrax Company was organized by Thomas Stanley Curtis (shown on the right), its first president and
general manager, in Los Angeles to manufacture superduty firebricks and fine porcelain products. Other directors were Charles R. Harris and B.L.
Wright. The officers were W.H. Hopper, vice-president; Dennis Hogan, secretary; and B.L. Wright, treasurer.
The capital stock was $500,000.
Thomas Curtis was a renowned
inventor, with 26 patents, whose products were the impetus for this new company. Curtis was born in Red Bank, New Jersey, in 1889.
He attended Shrewsbury Academy and the public schools in Red Bank. His plans to follow his father's career in the
medical profession was derailed by the death of his father in 1904, and having to support his mother and sister.
He found jobs in drafting, machine-shop practice, woodworking, and designing and constructing mechanical and
electrical equipment. It was during this period that he made his first invention, the three-blade shutter that
removed the flicker in early motion-picture projectors.
After writing some 50 articles for mechanical, electrical,
and photographic magazines, he was offered a position with a publishing house in Boston that issued the
American Photography and Electrician and Mechanic magazines. This work gave Curtis an opportunity to
establish an experimental laboratory where he developed high-frequency apparatus using an early X-ray equipment
that he had previously built with his father. This work and his articles drew the attention of the faculty at Massachusetts
Institute of Technology, who became frequent visitors to the laboratory. In exchange for consultation and use
of the equipment he had developed, the professors gave him private tutoring in mathematics, physics, and electrical
engineering. At the end of 1913, he went to New York to work part-time for a new magazine entitled Modern Mechanics.
There he established the Curtis Engineering Laboratories Company. At the same time, he took chemistry and physics
at Columbia University and metallurgy at Cooper Institute. He left the magazine company to start his own magazine
called Everyday Engineering, from which he issued a series of handbooks for experimental engineers and researchers.
He also published a book entitled High-Frequency Apparatus, Its Design and Construction.
By the end of 1916, Curtis was studying high-temperature reactions with gas-fired and electrically heated furnaces.
The latter included resistance, arc, and induction types. This work brought him into contact with Frederick G.
Cottrell, then Director of the Bureau of Mines in Washington. It was Cottrell that aroused his interest in
refractories, as also did Frank Antisell of the Raritan Copper Works. In April of 1917, Cottrell arranged a meeting
with the Naval Consulting Board and Curtis, which resulted in employing Curtis' laboratory to examine and test
military and naval inventions. In 1918, Curtis took the job of research technologist, with the commission of first
lieutenant, in the Gas Defense Division, Mechanical Research and Development Section of the Chemical Warfare
Service in Washington, D.C.
While visiting California during his Naval Board work, Curtis was impressed by the hugh quantities
of bauxitic clay seen on the dumps at Alberhill. After the war, Curtis went to Los Angeles to establish a small
laboratory to investigate a use for bauxitic clay. He made a deal with the Alberhill Coal and Clay Company
to experiment with the dump material. Within a year, Curtis found that the clay could be treated by high-temperature
means to eliminate its shrinkage completely and thus make it possible to manufacture the first high-grade
firebrick on the Pacific Coast. This resulted in the formation of the Vitrefrax Company.
The plant and office were built on two and a half acres of land at 5050 (or 5100) Pacific Boulevard and
East 51st Street in Vernon, Los Angeles County. High refractory clay was shipped to the plant from Alberhill
in Riverside County by railroad, which ran a spur to the plant. The main plant building was 70 feet by 250 feet and
constructed of wood frame and corrugated metal. The plant was equipped with a grinder, screens, and pug mill
to process the clay. Dry pressed brick machines were used to form the firebrick at a rate of 1,000 per day.
Initially, there were two round downdraft kilns, one of 50,000 capacity, to fire brick from electrically calcined
magnesite. There was also a rectangular kiln, which was later replaced by a third round downdraft kiln. Curtis' research
laboratory was in a separate brick building near the plant, where he developed new refractory materials. One of Curtis' son,
Eric Curtis, informed me about a fire that destroyed the original brick plant on October 15, 1922, but it was immediately rebuilt.
View of the original Vitrefrax plant. Photo courtesy of Eric Curtis.
The downdraft kilns were replaced in 1924 by a railway tunnel kiln that cost $35,000. The tunnel kiln was 93 feet long
and was started up on July 14, 1924. Each kiln car was eight feet three inches long, with a setting area four feet nine
inches wide by two feet high, capable of holding 400 brick. The cars traveled through the kiln at a rate of four feet per
hour and the products were fired to cone 26 (2,903 degrees F). The kiln had seven fire boxes on each side near the center.
Views of the wrecked Vitrefrax plant after the 1922 fire. Photos courtesy of Eric Curtis.
The plant was equipped with its own Curtis converter, which was used to make mullite. A mechanical separator
was used to purify the clay of impurities such as titanium, lime, magnesia, and alkalies.
Iron was removed by an electro-magnetic process. For this reason, the grinding equipment had to made of iron
instead of steel so that the abraded material could easily be removed. They ran day and night, seven days a week, with
View of the entrance to the tunnel kiln inside the Vitrefrax plant.
The stack on top of the kiln provided natural draft. From Ekstrand, 1925.
In addition to the high-alumina clay from Alberhill, the company obtained its materials from Santa Margarita Ranch,
aluminum oxide from Marysville, Utah, and kyanite from Ogilby in Imperial County, California. The kyanite deposit
was purchased in 1925, and was an important source for its mullite line of refractory and ceramic materials.
The first product produced was the ARGON brand of superduty firebrick, composed of purified clay and sillimanite.
This high-temperature refractory was used for gas-fired conditions in public utilities, oil industry, and most of
the sugar mills of the world, because of its resistance to bagasse ash. The ARGON line included an "AA" (All Alumina)
type, as well as five lower grades of alumina: 95 percent, 87 percent, 72 percent, 70 percent, and 60 percent.
Other brand names included CALIFORNIA MULLITE, DIAMEL, DYNON, DUROX, MAJOR, MOGUL, VITREFRAX, VITREFRAX CARBIDE,
VITREFRAX PERICLASE, VITCO, VITRELON, VITROX, and PLASTIC VITROX.
View of the end of the tunnel kiln inside the Vitrefrax plant.
The arches along the bottom kept the car wheels cool. From Ekstrand, 1925.
DUROX was the highest grade of the mullite line of refractories. It was used by the A. C. Spark Plug Company. DUROX
glass-tank block and shapes were used in the throat and finishing ends of glass tanks by glass manufacturers.
CALIFORNIA MULLITE was a lower grade of mullite refractory used in heavy-duty boilers. DIAMEL was a synthetic
magnesium aluminate spinel, widely used as a lining for red brass induction furnaces. DYNON was a recrystallized
corundum, produced through the aid of a mineralizer, cobaltic oxide, and developed primarily for electric insulators
of high tensile strength. VITROX series, introduced in 1925, contained a fiber structure made of kyanite, fibrolite,
or pyrophyllite, which increased the strength and resist cracking in the product. PLASTIC VITROX was made of trachyte
and a small amount of ball clay. These products were shipped throughout the U.S. and to countries as far away as
Spain, Italy, Belgium, and Asia.
View of the California Mullite brick in the tunnel kiln at the Vitrefrax plant. From Dietrich, 1928.
In 1925, the company reorganized and became a corporation. Harvey M. Brown was elected president, replacing Finley
M. Drummond, who was made vice-president and general sales manager. C.F. Allebrand was the production supervisor
and A.E. Small was the general manager. Thomas Curtis was the director of research. The company opened seven
national branch offices and warehouses. The eastern offices were in Philadelphia, New York, Cleveland, Chicago,
and Pittsburgh, and DeGraw-Booth-Stowe & Company of Illinois was the eastern sales organization of the firm.
The west coast offices were in Oakland and Portland. In 1934, the company terminated their research and development
laboratory. Thomas Curtis left the firm to establish his own laboratory in Huntington Park. The company closed the
plant shortly after 1950.
View of the interior of the Vitrefrax plant. From Dietrich, 1928.
Argon AA firebrick were standard, circle, and arch shapes. The circle brick has a salmon color with fine clasts up 1/16 inch across.
A subangular gray mineral, probably sillimanite, constitutes about 25 percent and the rest is composed of subangular fused alumina and
high alumina clay. On one side is impressed a rectangular name plate 3 1/2 inches long, 1 inch wide, and 1/16 inch deep. Inside the name plate, the
name "Argon AA" is recessed in title case serif letters that span a length of 3 3/8 inches. The "A" and "g" in Argon are 5/8 inch in height
and the "r," "o," and "n" are 3/8 inch in height. A recessed bar underlines the letters on each side of the "g." The block recessed letters "AA"
are 3/4 inch in height. A round screw imprint occurs on the left and right side of the rectangular name plate. This brick was made using the dry-press
process. Length 5 3/4 to 5 1/2, width 4 7/8, height 3 inches.
View of the side of the Argon AA circle firebrick.
Argon AA firebrick standard brick is buff and uniform in color. The edges are straight and sharp and the corners once sharp are broken. This brick
spalls easily. The surface is smooth with tiny pits. Stack indentation are present on the sides. On the marked face is centered a slightly raised
rectangular name plate 4 5/8 inches long and 1 5/8 inches wide. Centered and recessed inside the rectangular plate is the brand name "Argon"
in title case serif letters that span 4 1/4 inches in length and 1 inch in height for the upper case "A" and 5/8 inch in height for the lower
A recessed bar underlines the letters on each side of the "g." Offset to the right in recessed block letters are "AA" that spans 1 1/4 inches and
3/4 inch in height. Six round screw imprints are seen in the corners and near the edges of the brick. The interior contains granular grains
of blocky to subrounded welded cream alumina silicate, ranging up to 1/8 inch in diameter,
and about 2 percent white subangular quartz. This brick was made using the dry-press process. Length 9 1/4, width 4 1/2, height 2 1/2 inches.
View of the marked face of the Argon AA firebrick. Photo courtesy of George L. Kennedy.
The ARGON AA firebrick split is dry-pressed with a smooth surface and minor tiny pits. The edges and corners are sharp.
The faces display extremely fine longitudinal striations, probably imprinted from the press. On the marked face is a rectangular
name plate with rounded corners that is 4 7/8 inches long and 1 7/8 inches wide, containing the brand name on two lines in
recessed block letters. The first line contains the name "ARGON," which spans 4 1/4 inches and stands 3/4 inch in height. The
second line contains AA, which spans 1 3/4 inches and is 3/4 inch in height. The example shows external orange iron staining.
The interior consists of mostly subangular white fused alumina less than 1/8 inch across, some visible on the surface.
Length 9, width 4 1/2, height 1 1/4 inches.
View of the marked face of the ARGON AA firebrick. Donated by Brian F. Smith & Associates, Archaeologists.
Vitrefrax Corp. Argon AA firebrick was made since 1925, when Vitrefrax became a corporation, as indicated by the VITREFRAX CORP.
imprinted on the first line. Argon AA is on the second line. LOS ANGELES U.S.A. is on the third line. These letters are recessed inside
a slightly raised rectangular name plate with rounded corners. A round screw imprint is present above the "r" in Argon and below
the "A" in AA. Note the floating periods in U.S.A. This brick is similar to the Argon AA described above.
View of the marked face of the VITREFRAX CORP. Argon AA firebrick. Photo courtesy of George L. Kennedy.
Vitrefrax Corp. 2 Argon AA firebrick was made since 1925, when Vitrefrax became a corporation, as indicated by the VITREFRAX CORP.
recessed on the first line, that spans 3 inches with the "V" and "C" being 3/8 inch in height and smaller letters 1/4 inch in height.
2 Argon AA is on the second line, that spans 5 1/2 inches with "2" being 1 inch in height, "A" and "g" being 13/16 inch in height, and the
other letters 1/2 inch in height. Letters "A," "r," "o," and "n" are underlined. LOS ANGELES U.S.A. is on the third line, that spans 4 1/4 inches,
with "L," "A," "U, "and "S" being 5/16 inch in height, the other letters 1/4 inch in height. The names are recessed inside a rectangular name plate
with rounded corners, that spans 4 3/4 inches in length and is 1 3/4 inches in height. On the left side of the name plate, the number "2" is inside
a rectangular name plate that spans 1 inch and stands 3/4 inch in height. A round screw imprint is present inside the "A" in Argon and below
the "A" in AA and these are 1/4 inch in diameter. Note the floating periods in U.S.A. This brick has an arch-shape. It is buff with a rough, gritty,
crackled, and pitted surface. Edges are straight and sharp. Corners are broken. Brick spalls easily. Interior contains 2 percent subangular white
quartz and 1 percent round brown iron oxide spots, up to 1/8 inch in diameter, in a porous, granular, buff alumina silicate body. This brick was
made using the dry-press process. Length 9, width 4 1/2, height 2 3/8 to 1 3/4 inches.
View of the marked face of the VITREFRAX CORP. 2 Argon AA firebrick.
View of the end of the VITREFRAX CORP. 2 Argon AA firebrick showing the arch shape.
The No. 2 Argon 72 firebrick is a type 2 wedge-shaped brick with a 72-percent alumina content.
This brick was used for insulating boilers. The salmon colored brick was made using the dry press process.
View of the face of the No. 2 Argon 72 wedge firebrick. Photo courtesy of Bryan Jeffery.
View of the side of the Argon RK circle firebrick.
View of the face of the MAJOR firebrick. Blacky Blackwell Collection.
View of the face of the MOGUL firebrick. Donated by James Freedner.
MOGUL 3 is a wedge-shape firebrick of salmon color. The surface is rough and gritty. Edges are straight and sharp. Corners are broken. This brick spalls
easily. On the marked face, the "3" is rotated 90 degrees counterclockwise, followed by the name "MOGUL" in recessed block letters and
these are inside a tightly bound rectangular name plate, which is offset to the left of center. The name plate is 4 1/2 inches in length and 11/16 inch
in height. The number "3" is 3/4 inch wide. The brand name MOGUL spans 4 7/16 inches and stands 11/16 inch in height. A round screw, 1/4 inch in diameter,
is inside the number "3" and there are at least 4 screw imprints, 3/8 inch in diameter, near the corners and edges of the brick, visible on the right half
of the brick. The interior contains 2 percent round brown iron spots, up to 1/8 inch in diameter, in a porous, granular, buff alumina silicate body. This
brick was made using the dry-press process. Length 9 1/8, width 4 1/2, height 2 1/2 to 1/2 inches.
View of the face of the 3 MOGUL firebrick.
View of the side of the 3 MOGUL firebrick showing the wedge shape.
VITCO firebrick is salmon and fine-grained, with grain widths up to 1/16 inch across. On one face is impressed
a rectangular name plate 4 5/8 inches long and 1 5/8 inches wide. Inside the name plate at the top is the brand name
VITCO in recessed block letters spanning 3 1/2 inches in length, with letters 3/4 inch high. Made by the dry press
process. Length 8 3/4, width 4 1/2, height 2 1/2 inches.
View of the face of the VITCO firebrick. Donated by James Freedner.
View of the face of the VITCO FIRE CLAY firebrick. Blacky Blackwell Collection.
View of the face of the VITCO firebrick. Blacky Blackwell Collection.
VITCO 2A is a salmon, medium-grained (3/8 inch across), wedge-shaped firebrick. Interior is composed of subangular white and gray
fused alumina. On one face is impressed the brand name "2A" in recessed block letters spanning
1 3/4 inches in length, with letters 3/4 inch high. Made by the dry press process. Length 9, width 4 1/4,
height 2 1/2 - 1 5/8 inches.
View of the marked face of the VITCO 2A wedge firebrick. Donated by James Freedner.
VITCO 3 is a dark salmon, coarse-grained (1/4 inch across), key-shaped firebrick. On one face is impressed
a rectangular name plate 4 5/8 inches long and 1 3/4 inches wide. Inside the name plate on the first line is the brand name
"VITCO" in recessed block letters spanning 3 1/2 inches in length, with letters 5/8 inch high. On the second line is a
"3" standing 5/8 inch high. The marks in the example are difficult to see. Interior is composed of subangular white and gray
fused alumina. Made by the dry press process. Length 9, width 4 1/2 - 3 1/8, height 2 1/2 inches.
View of the marked face of the VITCO 3 key firebrick. Donated by James Freedner.
VITCO soap firebrick is dark salmon and medium-grained, with subrounded grains up to 3/8 inch across. On one
side is impressed a rectangular name plate 4 3/8 inches long and 1 inch wide. Inside the name plate is the
brand name "VITCO" in recessed block letters spanning 3 1/2 inches in length, with letters 7/8 inch high.
Interior is composed of subangular white fused alumina. Made by the dry press process.
Length 9, width 2 1/2, height 2 1/4 inches.
View of the marked face of the VITCO soap firebrick. Donated by James Freedner.
American Ceramic Society Bulletin 13, no. 8, August 1934, p. 21.
Copyright © 2009 Dan Mosier
American Ceramic Society Bulletin 13, no. 12, December 1934, p. 347.
American Ceramic Society Bulletin 16, no. 6, June 1937, p. 264-268.
A.S.M.E. Mechanical Catalog and Directory, American Society of Mechanical Engineers, v. 40, 1951, p. 369.
Brick and Clay Record, v. 57, no. 11, 1920, p. 941.
Brick and Clay Record, v. 59, no. 2, 1921, p. 134.
Brick and Clay Record, v. 65, no. 3, 1924, p. 190.
Brick and Clay Record, v. 66, no. 11, 1925, p. 838.
Brick and Clay Record, v. 67, no. 2, 1925, p. 128.
Brick and Clay Record, v. 67, no. 5, 1925, p. 350.
Brick and Clay Record, v. 67, no. 7, 1925, p. 483.
Brick and Clay Record, v. 68, no. 2, 1926, p. 134.
Curtis, Eric, written communications, 2014.
Dietrich, Waldemar F., The Clay Resources and the Ceramic Industry of
California, California State Mining Bureau Bulletin 99, 1928, p. 121-122.
Ekstrand, E. W., Positive Heat Transfer in Tunnel Kiln, Brick and Clay Record, May 12, 1925, p. 753-754.
California, The Iron Age, v. 106, no. 21, November 18, 1920, p. 1381.
Los Angeles City Directories, 1924-1942.
Pacific Mining News of the Engineering & Mining Journal-Press, Refractories From Western Minerals,
v. 2, no. 7, July 1923, p. 220.
Symons, Henry H., California Mineral Production and Directory of Producers For 1943,
California State Mining Bureau Bulletin 128, 1944, 222 p.
Vitrefrax Company Plant Destroyed by Fire, Chemical and Metallurgical Engineering, v. 27, no. 17, October 23, 1922, p. 850.
Western Machinery World, v. 12, March 1921, p. 134.