Welders are tools that join metal by melting the base material and, in most processes, adding a filler metal to form a strong joint. Welding on a homestead is used for fabrication, repair of equipment and fencing, and construction of structures. The four primary welding processes for homestead use are shielded metal arc welding (stick), gas metal arc welding (MIG), flux-cored arc welding (FCAW), and gas tungsten arc welding (TIG). Each process has advantages in cost, portability, material compatibility, and skill requirements. [[Welding Safety]] covers the protective equipment and precautions needed for all welding processes.
Shielded metal arc welding, commonly called stick welding, uses a consumable electrode coated in flux. The flux creates a gas shield that protects the weld pool from contamination. Stick welding is the most portable and affordable process, with machines available for under 300 dollars. It works well on rusty or dirty metal and outdoors in wind, but produces significant spatter and slag that must be cleaned. Common electrode types include 6010 for deep penetration on rusty metal, 6013 for clean, general-purpose welding, and 7018 for high-strength structural welds.
Gas metal arc welding, or MIG, uses a continuously fed wire electrode and a shielding gas, typically a mixture of 75 percent argon and 25 percent carbon dioxide. MIG welding is the easiest process to learn and offers the highest productivity for thin to medium thickness steel. It produces clean welds with minimal spatter. MIG machines range from 110-volt models for light fabrication to 220-volt models for structural welding on material up to 12 millimeters (1/2 inch) thick. Flux-cored welding (FCAW) is similar but uses a wire containing flux, eliminating the need for external shielding gas.
Gas tungsten arc welding uses a non-consumable tungsten electrode and a separate filler rod. TIG welding produces the highest quality, most precise welds and is suitable for thin materials and non-ferrous metals including aluminum and stainless steel. It requires significantly more skill and is slower than MIG or stick welding. TIG machines cost 500 to 3000 dollars and require both argon shielding gas and, for AC TIG welding of aluminum, a machine with adjustable AC balance and frequency.