Resistance welding is one of the oldest of the electric welding processes in use by industry today. The weld is made by a combination of heat, pressure, and time. As the name resistance welding implies, it is the resistance of the material to be welded to current flow that causes a localized heating in the part. The pressure exerted by the tongs and electrode tips, through which the current flows, holds the parts to be welded in intimate contact before, during, and after the welding current time cycle. The required amount of time current flows in the joint is determined by material thickness and type, the amount of current flowing, and the cross-sectional area of the welding tip contact surfaces.

Resistance welding is accomplished when current is caused to flow through electrode tips and the separate pieces of metal to be joined. The resistance of the base metal to electrical current flow causes localized heating in the joint, and the weld is made. The resistance spot weld is unique because the actual weld nugget is formed internally with relation to the surface of the base metal.

The PSW and SSW Series of water-cooled resistance spot welders offer the power needed for light fabrication and sheet metal work. Choose the features you need including stationary and portable models, and output ratings of 10kVA at 50%, or20kVA at 40% duty cycle (based on 10 seconds). The 10 kVA units weld materials up to 3/16 in (4.7 mm) total thickness, and the 20 kVA units can handle total thicknesses up to 1/4 in (6.3 mm). All PSW and SSW spot welders operate on single-phase input power. The PSW Series (portable models) feature the maneuverability often required in production line environments. The SSW models are designed for stationary use and come with an all-steel pedestal which houses timers and controls, as well as air and water connections. Portable and stationary air-operated models can be powered from a minimum of 60 PSI (920 kPa).