K3924-1 - Lincoln Electric Weld-Pak 90i FC Wire Feed Welder

Compact Inverter Flux-Cored Welding System

The Lincoln Electric K3924-1, commercially known as the Weld-Pak 90i FC, is a dedicated Flux-Cored Arc Welding (FCAW) power source designed for portability and ease of use in light-duty applications. Utilizing modern inverter technology, this machine significantly reduces weight and footprint compared to traditional transformer-based welders, weighing in at approximately 15 lbs (6.8 kg). This makes it an optimal solution for maintenance personnel, hobbyists, and contractors requiring a highly mobile welding unit for field repairs or home projects.

Operating on standard 120V input power, the Weld-Pak 90i FC delivers an output range of 30 to 90 Amps. It is capable of welding mild steel thicknesses ranging from 24 gauge up to 1/4 inch (6.4 mm). The unit features a simple two-knob interface for voltage and wire feed speed, allowing for infinite adjustment within the machine's range to dial in the perfect arc characteristics. Unlike tapped settings, this infinite control enables precise heat input management, which is critical when working with thinner materials to prevent burn-through.

The machine is designed exclusively for the self-shielded flux-cored process, eliminating the need for external shielding gas cylinders, regulators, or hoses. This further enhances its portability and simplifies the setup process. The K3924-1 includes a built-in wire drive system compatible with 0.030" (0.8 mm) and 0.035" (0.9 mm) flux-cored wires. Safety features include thermal overload protection, which automatically shuts down the output if the duty cycle is exceeded or airflow is blocked, protecting the internal components from damage.

Technical Specifications

• Input Power: 120V / 1 Phase / 60 Hz


• Rated Output: 90A at 18.5V, 20% Duty Cycle


• Input Current: 20A


• Wire Feed Speed: 40-500 ipm (1.0-12.7 m/min)


• Dimensions (H x W x D): 13.6 in x 8.9 in x 18.1 in