Table 8-1. - Current Selection Guide for GTA Welding of Common Metals

You can use table 8-1 as a guide for selecting the current for welding some of the more common metals. For more specific information, refer to the operator's manual for the specific machine you are using.

Torches

GTA welding torches are designed to conduct both welding current and inert gas to the weld zone. The torches can be either air or water cooled, depending on the welding current. Air-cooled torches are used for welding light-gauge materials at relatively low-current settings. Water-cooled torches are recommended for currents above 200 amperes. A sectional view of a GTA water-cooled torch is shown in figure 8-7. When you are using this type of torch, a circulating stream of water flows around the torch to keep it from overheating.

Figure 8-7. - GTA water-cooled torch.

NOTE: To avoid torch overheating caused by clogging and flow restrictions, you must keep the water clean.

The GTA welding torch carries the welding current and directs the gas to the weld area. The torch must have

Figure 8-8. - GTA torch parts.