76 GMAW/FCAW Handbook Copyright Goodheart-Willcox Co., Inc. Summary • After the type and thickness of material and transfer mode are determined, variables to be established include wire feed speed (amperage), voltage, electrode extension, travel speed, and travel direction. • The welding voltage determines the arc gap established between the end of the electrode and the workpiece. • Increasing wire feed speed increases welding current, and decreasing feed speed decreases welding current. • Increasing electrode extension causes more resistance heating of the wire and a lower welding amperage. Decreasing the electrode extension has the opposite effect. • Advantages of backhand welding are a more stable arc, less spatter, and deeper penetration. Forehand welding results in more spatter, less penetration, and better visibility of the weld seam. • Gun angle affects weld penetration, bead form, and fi nal weld bead appearance. fi • The two types of patterns used for depositing metal are the stringer bead pattern and weave bead pattern. • A weld schedule is a document listing the variables required to produce a desired weld. Review Questions Answer the following questions using the information provided in this chapter. 1. With a constant voltage machine, the _____ estab- lishes the welding current. 2. The arc gap between the end of the electrode and the workpiece is determined by the welding _____. 3. Increasing the electrode extension causes more resistance heating of the wire and a(n) _____ welding amperage. 4. What does the term stickout refer to? 5. List three advantages of backhand welding. 6. _____ angles generally range between 10° and 25° off perpendicular. 7. The weave bead pattern requires a(n) _____ at the end of each weave to fi ll the metal into the fi weld without undercut. 8. Downhill welding is commonly referred as _____. 9. A weld bead pattern made with side-to-side motion is commonly called a(n) _____ bead. 10. A weld _____ contains information about the weld joint design and the welding parameters and variables.