ELEMENTS OF SUCCESS: HOW AIR AND WATER COOLING MAY AFFECT WHICH EQUIPMENT YOU PURCHASE

When choosing between water-cooled and air-cooled equipment, weighing the cost, location, amps, duty cycle and operator comfort will help you determine which equipment can optimize your welding performance.

It doesn’t rise to the level of “to be or not to be,” but for many fabricators and manufacturers, deciding between an air-cooled versus a liquid-cooled MIG welding system can be a pretty vexing task.

Whether it’s air or liquid, cooling prevents the power cable, gun and consumables from overheating and reduces the potential for operator fatigue and injury. Choosing between air cooling versus water cooling requires a complex and careful analysis of your specific welding application and, in particular, the following five factors:
• Cost
• Work site location
• Amperage requirements
• Gun weight, and
• Operator comfort

WATER-COOLED VS. AIR-COOLED GUN BASICS
As their name implies, air-cooled guns use ambient air and shielding gas to dissipate excess heat that builds up in the consumables, neck and cable. Likewise, a liquid-cooled gun uses a liquid solution that is channeled through the power cable and circulated into the gun’s neck and consumables to physically absorb and carry away the heat that builds up in these same components. The differences don’t stop there, however.

The power cable on an air-cooled gun contains more copper than the cable on a water-cooled gun to help prevent the cable insulation from melting or possibly burning. Because water is more efficient than air at carrying away heat, a water-cooled system requires less copper in the power cable, making both the cable and gun lighter and smaller than in an air-cooled system. Unlike air-cooled systems, water-cooled systems require a radiator cooling system, which circulates the cooling liquid to dissipate heat from the gun.

CONSIDERATIONS
Cost. Water-cooled guns carry higher initial and ongoing costs than air-cooled systems, but that doesn’t necessarily mean that they cost more overall. When chosen for the right applications, the higher costs of water-cooled systems can be offset by increased productivity. The flexible cable, lighter weight, and smaller size of a water-cooled system can provide more operator comfort when compared to the similar-amperage air-cooled gun or torch. If you’re welding for an extended period of time at the upper amperage range of the gun, a heavier air-cooled gun may increase your fatigue and might require downtime for cooling.

Lower consumables cost is another potential advantage of a water-cooled gun. The radiator cooling system allows the tip, nozzle, and/or diffusers to run cooler than with an air-cooled torch, so consumables typically will last longer on water-cooled guns, helping reduce downtime associated with consumable changeovers.

But an air-cooled gun also provides several advantages. For example, it works well on lower-amperage applications and, in many cases, can meet the demands of most industrial applications while still providing the same performance at a fraction of the operating and maintenance costs.

Work Site Location. When choosing between air-cooled versus water-cooled guns, also consider the location of the work site. Air-cooled guns are more practical for outdoor work sites because they require fewer parts. This simplifies transport, setup procedures, and parts management.

Water-cooled guns generally are better-suited for shop use. They’re available in high-amp and low-amp options, but require a separate cooling system that can make them unwieldy on job sites where portability is a concern.

Amperage Requirements. Both air-cooled and water-cooled guns are available for welding up to 600 amps at 100 percent duty cycle. In general, however, a water-cooled gun is usually recommended for very high amperage (450 amps to 600 amps) MIG welding because the size and weight of an air-cooled torch can lead to operator fatigue.

Whether selecting an air-cooled or a water-cooled gun, it is also important to select a gun that is appropriately matched to the amperage requirements of the application. If, for example, an application demands that most of the day be spent welding at 150 amps, but that a few short welds be made at 300 amps, it doesn’t necessarily mean that the company should purchase a 300 amp gun. A 150 amp gun would likely be able to weld for short periods at 300 amps, and would certainly result in less operator fatigue by the end of the day than a 300 amp gun.

Closely related to amperage capacity is duty cycle (the percentage of time in a 10-minute period that the torch can be operated at a specific output without overloading). Because there is no standardized system for MIG gun ratings, a gun might be labeled as a 150 amp gun, but only able to weld at that level at a 40 percent duty-cycle. Likewise, another gun rated to 150 amps might be able to weld at that level at 100 percent duty cycle. Regardless of whether an air-cooled or water-cooled gun is selected, be sure to verify that the product is able to weld at the duty-cycle required by the application.

Choosing between water-cooled and air-cooled equipment comes down to your requirements for cost, location, amps, duty cycle and operator comfort. Both air-cooled and water-cooled torches and guns perform similarly when used correctly. Weighing identical variables when investigating these systems will help you determine which equipment will help you optimize your welding performance.