California brick
CALIFORNIA BRICKS


Kraftile Company

History

The Kraftile Company incorporated in 1925, with founders J. L. and C. H. Kraft, A. C. Myers, president, E. Ridgeway and H. E. Leash, directors. The plant was built in 1926 at 800 Kraftile Road in Niles, CA. The office was at 55 New Montgomery Street in San Francisco.

Local red clay was mined from a 100-foot trench, 35 feet deep, on the property by a bulldozer. The clay was mixed with barium carbonate and waste tile in a dry-pan grinding mill. It was ground to 20-mesh and the oversize was returned for regrinding. Water was added as it entered the twin screw Hummer auger where it was mixed, blended, and extruded as a block ribbon to an American wire cutting machine. The cut units were then passed to a 15-foot conveyor belt from which they were hand-loaded onto cars running on 24-inch rails. The cars were hand-trammed a short distance to carriages running on standard gauge track set normal to the narrow track. The carriages transported the cars to the entrance of the drying tunnels where they were transferred to narrow-gauge tracks running through the hot air dehydrator drying tunnels. There were eight gas-fired tunnels about 75 feet long equipped with two sets of 24-inch rails. Drying required 48 to 120 hours. These were later replaced by solar-heated driers. Firing took place in one of the five round down-draft 25-foot diameter kilns. Each kiln was equipped with 10 burners. Draft for the group of kilns was provided by two square stacks about 50 feet high. Bricks remained in the kilns 12 to 15 days to allow for pre-heating and cooling. Firing temperature was about 1,900 degrees F, maintained by pyrometric cone and pyrometer.

This company manufactured glazed structural wall and partition units, glazed swimming-pool- overflow gutters, patio tile, quarry tile, standard brick, Roman face brick, split pavers, enameled brick, acid-floor brick, and acid-tank block. These products were used in hospitals, schools, food product plants, factories, restaurants, stores, and public buildings throughout the country.

In 1955, California Division of Mines published a tour of the plant entitled "From Clay to Tile," which is reprinted here in part:

Kraftile yard
View of stacks in yard and overhead conveyor belt. Under tarpaulins
are various types of clay to be properly mixed in the batching room.

Kraftile yard
Batching room where several kinds of clay may be automatically mixed,
including local clay and clay from other parts of the state. To each
batch, barium carbonate is added to reduce efflorescence.

Kraftile yard
Clay after being batched, ground, and mixed with water, is extruded
in long bar shape onto conveyor. Shown here is clay being extruded
and cut. Wires cut 6 blocks to required tile length.

Kraftile yard
Special tiles for odd shapes and special trim are
shaped by hand, using potters wheel and hand tools.

Kraftile yard
After cutting and shaping, tile is glazed. In making glazes, a wide
variety of mineral materials is used: barite, feldspar, china clay,
and many others. Quality and color of the fired glaze are of primary
concern. Glaze may be applied to clay ware by spraying, painting, or
dipping. Here unfired clay tile is loaded onto belt for spray glazing.

Kraftile yard
Shown here is one method of glazing, utilizing
air spray. Tiles move on belt past glazer.

Kraftile yard
Loading kiln cars with unfired hollow tile that has been spray glazed.
Glazes are tested before use. One test utilizes steam under pressure in
boilers; if glaze develops cracks that show up as spidery pattern upon
being covered with ink, glaze is rejected.

Kraftile yard
Loading unfired ware into tunnel drying kiln.

Kraftile yard
After passing through drying kiln, ware may be fired in one of several
kilns. Kilns used in industry include field kilns, downdraft kilns (such
as the beehive shown here), tunnel kilns, and various types of specialty kilns.

Kraftile yard
Unloading fired tile from kiln.

The Kraftile plant operated five and a half days per week. The plant capacity was 1,000 tons per month. 85 were employed in the office and plant. The plant closed in 1996 and the buildings were razed a few years afterwards. The site has been developed for housing. Some of the bricks salvaged from the two stacks and some of the tile were used to make the entrance gate to the new subdivision.

Kraftile yard
View of the Kraftile Company plant, Niles, CA.

Kraftile Company Brick

Split Paver

Split paver is dark red, uniform in color. The face and sides are smooth. Two thin sides of the paver has three deep longitudinal grooves running the whole length of the brick. On one of these sides is imprinted "KRAFTILE CO NILES CALIF" in repeated fashion. Length 8, width 3 7/8, height 1 1/4 inches.

Kraftile split paver
View of the side of a Kraftile split paver displaying company name and location.

Kraftile split paver
View of the face of a Kraftile split paver.

Kraftile split paver
View of the end of a Kraftile split paver.

Split paver is orange-red to red, uniform in color. The face and sides are smooth with longitudinal short grooves giving a matte finish. Tiny specs of white subangular quartz less than 1/16 inch across are visible on the surface and constitute about 1 to 2 percent of the clay body. Some faces display a single groove running longitudinally through the center of the face, while others display transverse curved striations. Length 8 3/8, width 3 3/4, height 1 1/4 inches.

Kraftile split paver
View of the face of a Kraftile split paver at the El Cerrito Plaza BART station.

Kraftile split paver
View of the face of a Kraftile split paver at the San Leandro BART station.

Kraftile split paver
View of the face of a Kraftile split paver at the Los Angeles Mall, Los Angeles.

Patio Brick and Tile

Patio brick is brown and uniform in color. Surface is smooth. Edges are straight and sharp except for the short edges around the sides, which are rounded. Corners are sharp. Faces display curved wire-cut grooves and many show a surface undulation normal to the wire-cut giving it a wavy texture. Another variety displays faces with longitudinal grooves giving a matte texture. The interior contains about 4 percent white subangular quartz up to 1/8 inch across. The clay body is compact. This brick was made using the stiff-mud process, extruded, and wire-cut on the faces. It is a short and narrow brick with length 7 3/4, width 2 1/2, and height 1 5/8 inches.

Kraftile patio brick
View of the face of a Kraftile patio brick at the Los Angeles Mall, Los Angeles, displaying the wire-cut marks.

Kraftile patio brick
View of the smooth end of a Kraftile patio brick at the Los Angeles Mall, Los Angeles.

Kraftile patio tile
View of the face of a Kraftile patio tile at the Los Angeles Mall, Los Angeles.

Kraftile patio tile
View of the sides of a Kraftile patio tile at the Los Angeles Mall, Los Angeles.

Kraftile patio tile
View of the face of a Kraftile patio tile at the Los Angeles Mall, Los Angeles, with a matte texture.

Kraftile patio brick and tile
View of the Kraftile patio brick and tile at the Los Angeles Mall, Los Angeles.


References

California Division of Mines, From Clay to Tile, Minerals Information Service, Nov. 1955, v. 8, no. 11, p. 6-7.

Daily Review, Oct., 11, 1984, p. 29.

Davis, F.F., Mines and Mineral Resources of Alameda County, California, California State Mining Bureau, 1950, v. 46, no. 2, p. 292-293.

Dietrich, W.F., The Clay Resources and the Ceramic Industry of California, California State Mining Bureau Bulletin 99, 1928, p. 41.

Kraftile Co., A Complete Line of Enameled Clay Products, No date.

Kraftile Co., Split Pavers, 1986.

Copyright 2005 Dan Mosier

Contact Dan Mosier at danmosier@earthlink.net.