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Midland Tool

Miller Big Blue® 800 Duo Pro Diesel Welder / Generator

Item # 907587 Category Tag
  • Ideal for dual-operator applications on labor intensive job sites or job sites with limited space
  • 800 amps of weld power and 27,000 watts of generator power
  • Two independent arcs with up to 400 amps each. Or plug in additional inverters for a true multi-operator work platform
  • Allows the arc characteristics to be changed for specific applications in Stick, MIG, and FCAW
  • The cleanest, greenest diesel power available. Utilizes Diesel Oxidation Catalyst (DOC) technology in T4F models to keep the air clean with NO exhaust after treatment maintenance



Maintenance and Repair
Mechanical Contracting
Mining Maintenance
Pipe Fabrication / Construction
Railroad Maintenance

Power Type



Air Carbon Arc Cutting and Gouging (CAC-A)
Flux Cored (FCAW)
Stick (SMAW)
Stud Welding (1/2 inch
13 mm)
Submerged Arc (SAW)

Weldable Metals

Stainless Steel

Carbon Diameter


Welding Mode

CC/DC (Stick/TIG)

Output Mode

Paralleled (combined)
Separate (dual outputs)

Paralleled Output Range

CC/DC (Stick/TIG): 40-800 A
CV/DC (MIG/FCAW): 14-40 V

Paralleled Rated Output

CC/DC (Stick/TIG): 700 A at 44V
800 A at 38 V
CV/DC (MIG/FCAW): 750 A at 40 V
800 A at 38 V

Separate Output Range

CC/DC (Stick/TIG): 20-400 A
CV/DC (MIG/FCAW): 14-40 V

Separate Rated Output

CC/DC (Stick/TIG) 400 A at 36 V (each side)
CV/DC (MIG/FCAW): 400 A at 34 V (each side)

Max Open Circuit Voltage

15 VDC (Sense voltage for Stick and Lift-Arc™ TIG)
85 VDC

Gen. Power Rated at 104° F

1-Phase: 15000 watts peak; 12000 watts continuous
3-Phase: 27000 watts peak; 20000 watts continuous

Engine Model

Deutz TD 2.9 L4

# Engine Cylinders


Engine Type

EPA Tier 4 Final Compliant
Includes 120 V block heater
Liquid-cooled industrial diesel


65.7 HP

Weld Speed

1800 RPM

Idle Speed

1350 RPM

Fuel Capacity

25 gal

Oil Capacity

8.5 qt

Coolant Capacity

16 qt

Standard Shutdowns

High coolant temperature
Low fuel
Low oil pressure


46" H x 28-1/2" W x 69-1/2" L
To top of exhaust: 53.75"


1869 lbs


Optional Trailer Mount