Vertical welding with flux core LN-25 mig gun FCAW

Learning to weld vertical up with FCAW (Flux-Cored Arc Welding) can feel like trying to defy gravity, but trust me, it's totally achievable with the right approach and a bit of practice! I remember my first attempts – lots of drips and frustration, but I stuck with it, and now it's one of my most reliable techniques. If you're struggling, or just starting out, here’s what I’ve learned that really makes a difference. First off, getting your machine settings dialed in is crucial. For vertical up, I usually find myself bumping up the voltage just a hair compared to flat positions. This helps keep the puddle fluid enough to work with, but not so hot that it sags immediately. Your wire feed speed (WFS) will, of course, need to correspond with that voltage. A good rule of thumb is to start with settings recommended for a flat position on your machine and then make small adjustments from there. For self-shielded flux core, polarity is typically DCEN (Direct Current Electrode Negative), while gas-shielded FCAW usually uses DCEP (Direct Current Electrode Positive). Always double-check your wire manufacturer's recommendations! Next up, let's talk about technique. The torch angle is super important – you'll want to maintain a slight upward angle, maybe 5 to 15 degrees, pushing into the joint. Unlike some other processes, with flux core, you generally drag the gun, meaning the nozzle points back towards the completed weld. This allows the flux to do its job and protect the molten puddle. When it comes to movement, creating a 'shelf' for your weld metal to sit on is the key. I personally favor a slight Z-weave or C-weave pattern. Start on one side of the joint, move across the bottom of the previous bead, pause briefly on the opposite side to let the puddle build, then move up slightly and back across. That little pause on the edges helps fill the toes of the weld and prevents undercut. The goal isn't to move fast; it's to maintain a steady, consistent pace, watching that puddle like a hawk! If you move too fast, you risk lack of fusion, and too slow, you’ll end up with a saggy mess. One of the biggest challenges I faced was preventing the molten metal from sagging. If your weld starts looking like it's dripping down, it's usually a sign that your heat input is too high, or you're not moving fast enough, or your pauses on the edges aren't quite right. Try reducing your voltage slightly or speeding up your travel. On the flip side, if you're getting a narrow, ropey bead with poor penetration, you might be too cold or moving too quickly. Controlling your stickout – the length of the wire extending from the contact tip – is another small but significant detail. For vertical up, I usually keep it a bit shorter than I might for flat welds, typically 1/2 to 3/4 inch. This gives me better control over the arc and puddle. Don't get discouraged if your first few attempts aren't perfect. Vertical up welding requires a good feel for the puddle and consistent hand movement. Practice on scrap metal, adjust your settings, and pay close attention to how the puddle reacts. With enough patience and repetition, you'll be laying down beautiful vertical up FCAW beads in no time. Keep at it, and you'll master this essential welding skill!