Stick welding is more forgiving on unclean conditions, but it never hurts to clean parts with a wire brush or grind off excess rust. If you prepare well and have average welding ability, you can make a sound weld. However, even great welding skill cannot overcome poor preparation, as it can lead to cracking, lack of fusion and slag inclusions.
Common electrodes used for general work include 6010, 6011, 6013, 7018 and 7024, each of which has specific properties: 6010 electrodes penetrate deeply, while 6013 electrodes penetrate less. For much better bead appearance and work on higher strength steels (say for a hitch), use a 7018 rod. For better penetration on thick material, grind the joint to a 30 degree bevel (leave a nickel-width land on the bottom of the groove) and make multiple passes. Alternatively, make the first pass with a 6010 rod, then make a "cap" with a 7018. The 7024 rod is perhaps the easiest to use. Also known as a "drag rod," this electrode's thick flux automatically maintains the correct arc length, which allows you to drag the rod directly along the work piece.
Hardfacing rods can provide impact resistance, abrasion resistance or both depending on the application. Because the type of rod required depends on the type of soil or aggregate in your area, contact your local welding supply distributor and ask for their expert opinion.
Duty cycle is the number of minutes out of a 10-minute cycle a welder can operate. For example, the Thunderbolt XL creates a 200 amp DC output at 20 percent duty cycle. It can weld continuously at 200 amps for two minutes, and then must cool for eight minutes to prevent overheating.Duty cycle and amperage are inversely proportional. Operating at 90 amps, the Thunderbolt has a 100 percent duty cycle, meaning you can weld without stopping. This inversely proportional rule is true of all Miller machines but does not apply to all machines made by other companies.
A 225 to 300 amp machine handles almost anything the average person will encounter, as most Stick welding procedures require 200 amps or less. To weld material thicker than 3/8 in., simply make multiple passes - this is what professionals do, even when welding on 1 in. structural steel.
Yes, if you need to weld on material that's become magnetized from friction, such as when hay, feed or water constantly rub against a steel part. A DC output won't work because of "arc blow," where the magnetic field blows the molten filler metal out of the weld puddle. Because an AC output alternates between polarities, it enables you to weld magnetized parts.
A welder with an AC/DC output, whether its an electric arc machine like Miller's Thunderbolt or a gas engine drive like Miller's Bobcat.DC welding offers advantages over AC for most Stick applications, including: easier starts; fewer arc outages and sticking; less spatter/better looking welds; easier vertical up and overhead welding; easier to learn "how to weld" and a smoother arc. DC reverse polarity (electrode positive) provides about 10 percent more penetration at a given amperage than AC, while DC straight polarity (electrode negative) welds thinner metals better.