High Brightness Calcined Kaolin
Chemical index(%)
SiO2
Al2O3
Fe2O3
TiO2
CaO
Na2O
K2O
MgO
52.00±1
45.00±1
≤0.50
≤0.80
≤0.50
≤0.20
≤0.10
≤0.20
hysical Form
Highly Pulverized Powder
ISO Brightness (%)
95.5 Min.
Screen Residue, 325 Mesh (%)
0.005 max
Free Moisture @ 105 deg C (%) as produced
pH (28% solids)
6.0-7.0
Specific Gravity (g/cm3)
2.63
Sedigraph Particle Size (%<2μm)
Oil Absorption (g/100g )
63-68
Bulk Density (kg/m3)
400
Hegman
High brightness calcined kaolin Tianzhijiao Kaolin Branch Of Inner Mongolia Baotou Steel Hefa Rare Earth Co.,Ltd. , https://www.tzj-kaolin.com
0.5max
80±2
4.0min
Another installment in the history of turret wagons within the Chicago Fire Department, brought to you by Jack Connors. The images showcase "Big Mo" on two different chassis throughout its service life. Initially assigned as 6-7-2, it was mounted on a 1953 International 6×6 chassis, painted black over red. This unit carried shop number G-248. Later, it was re-chassis onto a 1957 GMC 6×6, now in the blue and white colors associated with Civil Defense, and renumbered to shop G-157.
The photos featured come from Jack’s collection, including images from Ken Little and George Brown, as well as Jack’s own personal shots. These pictures capture Big Mo in various settings, from emergency responses to parades and routine operations.
One image shows Big Mo working at a 5-11 alarm fire in June 1969 at 14th and Indiana, with special units on scene. Another captures the original version of Big Mo, built by CFD shops on the 1953 International chassis. A third photo shows it stationed at Engine 13’s house, while another highlights its presence at 66th & State. There's also a shot of Big Mo during a fire prevention week parade in October 1970, and one showing it at Engine 42’s station. Finally, a rare image from Ken Little depicts the second version of Big Mo at a fire scene, though the date and location remain unknown.
These historical snapshots offer a glimpse into the legacy of one of the most recognizable vehicles in the Chicago Fire Department's fleet.
If you're interested in more stories about the department's history, check out the previous post here. And for an earlier look at Big Mo 6-7-2, visit this link.