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Midland Tool

Miller Big Blue® 450 Duo CST Diesel Welder / Generator

Item # 907477 Category

The Big Blue® 450 Duo CST is a rugged, compact, fuel efficient diesel welder/generator that provides 2 superior arcs in one economical package.

  • Multi-function fuel gauge:  Displays fuel level and engine hours, and can be customized to set oil change interval reminders.  In the case of high coolant temperature, low oil pressure, or low fuel level, the engine will shut don to prevent damage or make restarting easier.
  • Adaptive Hot Start™ For Stick Arc Starts:  Automatically increases the output of a weld should the start require it.  Prevents the electrode from sticking and creating an inclusion.
  • Remote Amperage Control:  Provided through 14-pin receptacle on front of the machine, and permits use of standard and wireless remote amperage control devices.



Maintenance and Repair
Pipe Fabrication / Construction

Power Type



Air Carbon Arc Cutting and Gouging (CAC-A)
Stick (SMAW)

Weldable Metals

Stainless Steel

Carbon Diameter

Rated: 3/16" (paralleled)

Welding Mode

CC/DC (Stick/TIG)

Output Mode

Paralleled (combined)
Separate (dual outputs)

Weld Output Range

Paralleled: 10-450 A
Separate: 5-225 A (each side); 5-280 A (one side only)

Weld Output at 122° F

Paralleled: 350 A
27 VDC
100% Duty Cycle
Separate: 175 A
27 VDC
100% Duty Cycle

Max Open Circuit Voltage


Gen. Power Rated at 122° F

1-Phase: 10000 watts
120/240 VAC
60 Hz continuous
3-Phase: 12000 watts
240 VAC
60 Hz continuous

Sound Levels at 23 Ft

72.2 dB

Engine Model

Mitsubishi S4L2

# Engine Cylinders


Engine Type

EPA Tier 4 Final Compliant
Liquid-cooled industrial diesel


24.7 HP

Weld Speed

1800 RPM

Fuel Capacity

11.5 gal

Oil Capacity

6.3 qt

Coolant Capacity

10 qt

Standard Shutdowns

High coolant temperature
Low fuel
Low oil pressure


32" H x 26-1/4" W x 56" L


1064 lbs (without fuel)


Optional Trailer Mount