Of all welding techniques, vertical welding -- up or down -- presents unique complications.
Working with our welding consultant, Joel Ort of Hortonville, Wisconsin, DTN/Progressive Farmer put together this list of steps you can use to work through the challenges of vertical welding. We worked through this process using Ort's Miller MIG welder. But the techniques described here work for other welding techniques, as well.
-- Setup. This is the most important step. Vertical up and down welding is an exercise that works counter to gravity. Think about it: You convert welding wire to molten metal to stick together two pieces of steel.
You'll want to do two things here. First, reduce the voltage and amperage 10% to 15% from what your settings would normally be for this kind of work. The second step, Ort suggests, is to "practice, practice, practice" on scrap metal.
-- Bottom up or top down. For most vertical welding work, you'll want to start at the bottom and travel up. This is a direction that gives good penetration into metals 1/4 inch or thicker. You might want to weld from the top down when you're working with thinner material. This will help prevent burn-through, as you'll want to be pulling the gun away from the weld. It's best again to practice the weld. This will help you determine the best welding direction and the voltage and amperage settings, given the type of the metal being used.
-- Gun angle. When welding from the bottom, up angle the gun down slightly, about 5 to 15 degrees, from perpendicular. When welding from the top down, angle the gun 5 to 15 degrees down but in a position that puts the gun at an angle over the puddle.
-- Welding up. When welding up, the angle of the gun creates a hole in which you keep adding material. Use a back-and-forth weaving pattern. Some welders suggest that you pause briefly with each pass to give the weld a moment to cool. This method allows you to build a welding pass on the previous one. It's like laying bricks, one layer on top of another -- the weld remains below the gun. On thicker materials, you may need to make a "root pass." This is an initial welding pass followed by another pass over the top.
-- Welding down. For a vertical down weld, create an upside-down "U." You will also want to pause at the end of each pass. Make sure you keep the arc on the front edge of the puddle. You don't want the molten metal to run ahead of the arc.
Dan Miller can be reached at firstname.lastname@example.org
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