Tips for uphill MIG welding

Q: What patterns is used in uphill gas metal arc welding (GMAW), and what amperage should I use on 0.25-in. plate using 75 percent argon/25 percent carbon dioxide shielding gas? Where I work—I build farm equipment—there’s no need for uphill welding, so I like to practice at lunch.

A: Practice at lunch? That’s awesome!

Think of the vertical weld pool as a shelf you’re building. Keep it level as you move straight across side to side, or make a slight U downward into the weld pool. Move quickly through the center while hesitating on the sides to tie in to the base metal.

Get Into a Rhythm

Always watch both sides of the weld pool, and don’t get into the habit of counting. You’ll get a rhythm going, but you want to see it tie in before you move from the side. If you don’t tie it in properly, you’ll cut into the steel without depositing any filler metal. This is called undercut: the cardinal sin of weld defects.

Bead Size Considerations

I usually use from 0.125- to 0.25-in. stickout. A good technique to learn with is to weave a wide bead, from 0.75 to 1 in. As you master that, reduce your width until you can run small stringer beads about 0.25 in. wide. Always run your beads in the joint, not on the plain face of a piece of steel.

The first pass is the hardest one to control. You then have that bead to tie in to, making the next beads easier to run.

Fine-Tuning the Power

Every machine runs differently, but I usually use around 200 to 250 amps (wire feed) and 20 volts on mind. You can find-tune it from there. When it’s running right, it’ll sound like bacon frying. Good luck, and keep up that great work ethic!