Big Blue® 800 Duo Pro Engine-Driven Welder | MillerWelds

Big Blue® 800 Duo Pro

A complete multi-process & multi-operator engine driven welder that delivers two independent pipe quality arcs in one complete package. Equipped with ArcReach® technology, operators can change weld settings from the ArcReach feeder or remote. RMD® & Pulsed MIG welding capabilities are added with the ArcReach Smart Feeder.

Base Model

Wireless Interface Control

Get Total Control — Where You Work: Wireless Interface Control


Heavy-Duty Low-Speed DEUTZ TD2.9 L4 T4F Industrial Diesel Engine
The cleanest, greenest diesel power available. DEUTZ T4F models utilize diesel oxidation catalyst (DOC) technology to keep the air clean with NO exhaust after-treatment maintenance.
Multi-Arc Welding
One dependable engine - two independent arcs with up to 400 amps each (or 800 amps for a single operator). Plug in additional inverter welders for a true multi-operator (3+ arc) work platform!
Increased Efficiency
More arcs and better fuel economy equal increased profits for your business. Estimated savings are 34-percent with a dual-operator unit versus two single-operator units.
Advanced Features for the Professional Welder
  • Adaptive Hot Start™ makes starting stick electrodes easy without creating an inclusion.
  • Infinite arc control available in the Stick and Wire modes for easier fine tuning of tough-to-weld materials and out-of-position applications.
  • Lift-Arc™ TIG provides arc starting that minimizes the risk of electrode/work contamination without the need for high frequency.
Industrial USB Port
Quickly upload the latest software and download machine log files to retrieve in-depth information such as diagnostics and machine statistics.   Learn More
Dynamic DIG™
Unlike conventional DIG that provides a preset amount of short-clearing current, Miller’s proprietary Dynamic DIG works on a time-based algorithm that automatically adjusts the amount of current required to clear a short. What does this mean? A smoother more consistent arc that can be tailored to match application, material, fit-up, and welder technique.   Learn More
Increased Productivity & Safety
More arc-on time, and reduced exposure to slip, trip, and fall hazards can be realized using ArcReach because less time is spent going back to the welding power supply to set process and arc amperage or voltage.
Electronic Engine Display
Electronic engine display simultaneously displays fuel level, engine hours, coolant temperature, oil pressure, battery volts, and engine RPMs. Also tracks oil change intervals and displays engine diagnostics for quick and easy servicing.
Other Standard Features
Output contactor control, digital meters with SunVision™ automatic idle, thermal overload protection, and 120-volt engine block heater.
ArcReach Heater Compatibility
Take charge of your field preheat and bakeout applications up to 600 degrees Fahrenheit (315°C). This system uses induction heating to generate heat in workpieces, so welders can do their own preheating quickly and safely. A part of the ArcReach technology platform, the ArcReach Heater is an accessory for select ArcReach welding power sources.   Learn More
ArcReach® Technology
Exclusive ArcReach technology uses existing weld cables to communicate process adjustment commands back to the engine-driven welder. With an ArcReach system, amperage & voltage are conveniently located at the operator's fingertips - not back at the power source.   Learn More

Not Included

  • Weld leads



Regulated Metal Deposition (RMD)

General Specifications

Title Big Blue® 800 Duo Pro
Industries Interests Construction and Fabrication
Amperage 20 A - 800 A
Weldable Metals Stainless Steel
Rated Carbon Diameter 1/2 in (12.7 mm)
Current Type DC
Max Open Circuit Voltage 85 VDC
Portability Fork Pockets
Lift Eye (Standard)
Trailer (Optional)
Cold Weather Starting Aids Engine Block Heater
Glow Plugs
Engine Brand Deutz
Engine Compliance T4F
Engine Idle Speed 1350 RPM
Engine Weld Speed 1800 RPM
Fuel Tank Size 25 gal.
Fuel Type Diesel
Horsepower 65.7 hp
Weld Output CC / CV
Rated Output Separate (dual outputs, each side): CC/DC - 400 A at 36 V; CV/DC - 400 A at 34 V / Paralleled (combined):CC/DC - 700 A at 44 V, 800 A at 38 V; CV/DC - 750 A at 40 V, 800 A at 38 V
Single Phase Auxiliary Continuous Power 12000 W
Single Phase Auxiliary Peak Power 15000 W
Sound Rating Idle: 71.3 dB / Weld: 78.9 dB
Three Phase Auxiliary Continuous Power 20000 W
Three Phase Auxiliary Peak Power 27000 W
Applications Mobile Fabrication & MRO
Process Pipe
Net Width 28.5 in
Net Height 46 in
Net Length 69.5 in
Net Weight 1870 lbs
Warranty 3 Years
Miller's True Blue Warranty




Big Blue Application Image
Dual Operator Application Image
Lambeau Field Application Image


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