10401904 - Tweco Classic No. 4 MIG Gun, 400A, 15 ft, Tweco Connection

The Industry Standard for Heavy-Duty MIG Welding

The Tweco Classic No. 4 MIG Gun (Part Number: 1040-1904) is a legend in the welding industry, known simply as the "Number 4" by fabricators across North America. Designed for high-amperage applications, this air-cooled gun is rated for 400 Amps at 60% duty cycle when using CO2 gas, making it the go-to choice for structural steel, heavy equipment manufacturing, and general industrial fabrication.

This model features a 15-foot cable assembly, providing ample reach for working around large assemblies without moving the wire feeder constantly. The gun comes equipped with a standard Tweco-style rear connection, ensuring compatibility with a vast range of wire feeders and adapters commonly found in workshops. It is set up out of the box to handle standard wire diameters, typically ranging from .035" to .045" (0.9mm - 1.2mm), covering the most common welding tasks.

One of the primary advantages of the Classic No. 4 is its serviceability. It utilizes the widely available Tweco 14 Series contact tips, 24 Series nozzles, and 54 Series gas diffusers. This means replacement parts are easy to find and affordable, minimizing downtime. The rugged handle and durable cable outer jacket are built to withstand the harsh environments of shipyards, construction sites, and fabrication floors. When reliability is non-negotiable, the Tweco Classic No. 4 delivers consistent performance weld after weld.

Key Features

• High Output: 400A rating handles thick plate and heavy deposition rates.
• Durable Construction: Metal-jacketed conductor tube and impact-resistant handle.
• Easy Maintenance: Simple design allows for quick liner and consumable changes.
• Proven Design: The preferred gun design for decades of professional welders.