Farmers weld under some of the worst circumstances—painted or rusty metal, often outdoors and always in a hurry. We use arc welders inherited from our grandfathers and welding rods that have been stored in an open box under the welding bench since who knows when.
Because each one of these factors can diminish the quality of welds, here are a few tips to improve weld strength and appearance:
- Take time to prepare the pieces to be welded. No matter how well damaged pieces of metal fit together or how well pieces of new metal align, it is critical to prepare the metal for welding. Grind away all of the paint and rust within ½" of the future weld. When butt-welding two pieces together or when joining pieces thicker than 3⁄8", bevel the edges to 45° angles to improve penetration.
- Ground it properly. MIG-type wire welders require their ground clamps be fastened to bare shiny
metal. The closer the ground clamp is to the actual welding point, the better.
Arc welders that use welding rods are more forgiving about the quality and location of ground points. But making a point of grounding to bare metal near the welding point will only improve electrical conductivity that is the core of good welds.
- Use the welder correctly. MIG welders are best used indoors or behind a wind shield because even a slight breeze can disrupt the layer of shielding gas.
Arc welders ignore all but gale-force winds. They can weld through thin paint and mild rust, and they are the welder of choice for field repairs. Problems with arc welds are often related to electrode (or "stick") selection and age.
- Use rods according to the welding that is being done. Miller, Lincoln, Hobart and other welder manufacturers offer detailed information on the various sizes and types of welding rods on their websites. But let’s be honest—most of us keep a stock of either 1⁄8" diameter 6011 or 6013 rods and make it work for everything.
"Ideally, you use a welding rod appropriate to the thickness of the metal you’re welding," says John Leisner, product manager for Miller Welding, who does farm-style welding after-hours and weekends on his own projects. "But you can do a multi-pass weld with a small-diameter rod to equal the work of a bigger rod. The 1⁄8" is the most common diameter rod for farm use. For general repairs, I carry 3⁄32" and 1⁄8" 6011 and 6013 rods."
There are differences between 6011 and 6013 welding rods, but Leisner explains the differences in simple English: "6011 rods have more penetration, but the welds are a little rougher looking with a little more spatter; 6013 rods have a little less penetration and make a prettier weld with less spatter," he says. "If looks matter, I’ll make a multi-pass weld and use a 6011 rod at the bottom of the V and finish with a 6013 rod."
- Store welding rods properly. Welding rod flux absorbs moisture from the atmosphere, which degrades its shielding ability, makes it more difficult to strike and maintain an arc, and can create weaker uglier welds.
"For example, 7018 is a great welding rod," says Leisner, "but once the package is opened, you’ve only got 6 to 8 hours before you need to put it in a heated storage device to keep it
- Set the welder correctly. We’ve all made repair welds, only to have the metal beside the weld break.
"One of the causes of crystallized metal around welds is too much heat all at once," Leisner says. "It actually makes stronger welds if you make one pass, knock off the slag and weld a couple more passes. Add moderate heat with every pass, instead of a massive amount of heat in a single pass."
- Retire Grandpa’s welder. Leisner encourages farmers with welders more than 20 years old to investigate the latest generation of welders.
"If you’re welding with an old arc welder where you plug the cables into holes in the front of the welder to change amperage, you’ll think you’ve died and gone to heaven if you get a chance to weld with a new welder with integrated circuitry," he says. "It’s much easier to strike and hold an arc, and the welds are better as a result."
For field repairs, a simple four-compartment welding rod storage container keeps several types and sizes of welding rods handy and organized. A rubber gasket in the screw-on lid keeps humidity from contaminating flux on the welding rods. Around $20.