Nozzle made of copper or copper alloys. Copper has good thermal and electrical conductivities, so it's ideal for use as a heat-transfer element. Copper also has some disadvantages. It can be oxidized by air, water, and other chemicals. So special measures need to be taken to protect it against corrosion. And finally, it can be toxic if not handled properly during manufacturing or use. The most common application for gas welding nozzles is gas tungsten arc welding (GTAW). In this process, a continuous stream of filler material (such as steel) is fed into the weld puddle where it is melted by the heat of the arc. The nozzle creates a jet of hot gas that extends beyond the end of the welding rod. This blows away moisture from the joint being welded and provides additional shielding for the weld. Gas metal arc welding (GMAW) uses a similar setup except that the welding process takes place while the metal is in contact with both the electrode and the workpiece. Thus, there is no need for any additional material to fill in the gap between the pieces being joined.