David Anderson of Hobart Welders says he’s talking to more farmers who are interested in buying a MIG welder for machinery repairs. Why? Compared to a stick welder, a wire-feed MIG can weld thinner material (22 to 24 gauge) and can be used with a shielding gas for better puddle control and bead-wetting action. In addition, Anderson says MIG is an easier welding process to master. “After a few hours of practice, even a novice can create good-looking weld beads with a MIG welder,” he says.
Buying tips. For a high-quality MIG welder that runs on 115v household current, expect to pay between $400 and $600. These all-in-one MIG machines should come almost ready to run out of the box. “Be sure to buy a machine with a built-in gas valve and a regulator. Some ‘wire welding’ machines designed for gasless flux cored welding are sold without them,” Anderson says.
You also have to start with the right gas. Anderson says you’ll get the most flexibility and the least splatter out of a 75% argon and 25% CO2 mix (75/25). Straight CO2 requires more volts and a faster wire speed. Straight CO2 welds penetrate deeper, splatter more and produce a harsher, narrower bead with a higher crown.
Also make sure you have the right wire, contact tips, liners and polarity for your machine. For MIG welding, the correct polarity is DC reverse (also known as electrode positive). Many wire welders come set for straight polarity (electrode negative), which is used for flux cored welding. Follow the instruction manual to set the right polarity. For more tips on proper MIG welding technique, go to www.hobartwelders.com.
Hobart Handlers. Hobart sells two MIG welders: the Handler 135 ($529) and the 175 ($669). The company originally designed these all-in-one welder/wire feeder systems for professional use in the auto repair and rental industries, where fine sheet metal work is a priority, but they should work equally well when doing sheet metal repairs on most farm equipment.
These welders have a wide “sweet spot” so you won’t waste a lot of time trying to get the right adjustment. The sweet spot is the point where the operator adjusts the wire feed speed and voltage to produce the classic “sizzling bacon” sound that signifies a good arc. A wire speed tracking function makes finding that spot easier. When the voltage knob is switched to a different tap for a different metal thickness or joint design, the function automatically increases or decreases the wire feed speed with the change in the voltage setting.
The Handler 135 can weld 22 gauge up to 3/16-in. steel. It plugs into 115v household current, weighs 55 lbs. and delivers 30- to 135-amp output. The Handler 175 can weld 22 gauge up to 3/16-in. steel or 1/4-in. aluminum. It plugs into 230v current, weighs 65 lbs. and delivers 30 to 175 amps. Both machines handle mild steel, stainless, flux cored and aluminum wires. A dual-groove drive roll lets you change from .023/.025- to .030/.035-in.-dia. wire.
In addition to having an output capacitor to smooth the arc voltage, the Handler has a transformer and choke design that produces a softer, more desirable arc, according to the company. The Handler’s control and feedback circuits respond quickly to changes in the arc. Contact Hobart Welders, Box 100, Lithonia, GA 30058, 800/332-3281, www.hobartwelders.com.