Chapter 8 Gas Metal and Flux Cored Arc Welding 235 Copyright Goodheart-Willcox Co., Inc. 8.17 GMAW and FCAW Safety The safety precautions for arc welding covered in Chapter 1, Safety in the Welding Shop, and in other chapters of this book apply to GMAW and FCAW. The appropriate precautions must be taken to avoid ultra- violet and infrared rays from the arc, fl ying sparks and droplets of molten metal, electric shock, fumes, and burns. Always wear a helmet with an approved lens to protect your eyes and face from arc radiation. The shade number required increases as the amperage increases. A #11 lens is the minimum recommended. Lens shades up to #14 may be worn as required for comfort and for high current welding. Refer to Figure 7-44 for recommended lens shade numbers. When welding for long periods, wear fl ash goggles with a #2 lens shade under the arc helmet. Wear PPE recommended for GMAW and FCAW to protect all skin from radiation and hot metal burns. This PPE includes safety glasses, a welding helmet, steel-toed shoes, and gauntlet gloves. See Figure 8-75. Flying sparks present a hazard if they strike unprotected skin, lodge on fl ammable clothing, or hit other fl ammable material. Wear clothing made of fl ame-resistant materials, such as cotton and leather. Leather clothing offers the best protection from burns. Clothing should be of suffi cient weight to block any rays from the arc and dark in color to reduce refl ec- tion. Always wear welding gloves with cuffs that go over the sleeves on your shirt. Shirts should have long sleeves. Pants should be cuffl ess. To protect others from arc fl ash, shield the weld- ing area with nonfl ammable tarps in the fi eld or on a construction site. When welding indoors, weld in a booth or in an area shielded by welding curtains. Goodheart-Willcox Publisher Figure 8-75. This welder is wearing proper PPE for GMAW and FCAW welding. PPE includes safety glasses, a welding helmet with the proper lens shade, dark cotton clothes to cover all skin, steel-toed shoes, and gauntlet gloves. This welder is also wearing ear plugs. GMAW Troubleshooting Guide Trouble Possible causes How to correct Porosity See previous page, Dirty welds Dirty electrode wire Dirty base metal Inadequate gas shielding See previous page, Dirty welds See previous page, Dirty welds Cracked welds Improper technique Faulty design Faulty electrode Shape of bead Travel speed too fast Improper technique Rigidity of joint Change angle of gun to improve shielding Check edge preparation and root spacing Check electrode wire for compatibility with base metal Change travel speed or shielding gas to obtain more convex bead Slow down Change angle of gun to improve deposition Redesign joint, preheat and postheat, weave bead Welding and Fabricating Data Book Figure 8-74. (Continued).