In previous articles (Part I & Part II), I talked about how to choose and set up your equipment for oxy-acetylene welding. I also covered the basics of setting your torch correctly, so you have a nice neutral (equal parts oxygen and acetylene) flame. Too much acetylene and it will be sooty and add carbon to the weld puddle. Too much oxygen and the reaction causes the metal to burn, instead of smoothly melt.
Today, we’ll talk about actually running a bead. I’ll break it down into three main concepts: comfort, focus, and eye-hand coordination.
It’s hard to weld if you are uncomfortable. So, first and foremost you need to get into a comfortable, relaxed position.
For your first practice welds, I’d suggest positioning your workpiece flat on a level, non-flammable surface like a welding table. The surface should be about hip height. This way, you can lean against the table a little bit, so your arm doesn’t sway as you weld. Welding requires smooth, precise movements to create a strong and nice looking bead. Any swaying or jerking can cause the weld puddle to be uneven and weak. Even your breathing can affect the movement of the torch, if you aren’t paying attention.
Balance your body upright, just lightly bracing yourself against the table, not leaning into it. The farther you have to reach, the faster your muscles will become fatigued, making your torch unsteady. You’ll want the work close, but not so close as to catch your pants on fire.
Remember, when welding it’s much better to be relaxed and comfortable than out of position and tense.
You’ll know you’re a welder when you can pass the Carolina welding test. That’s where you have your helmet or goggles on and you’re focused on your bead welding away and one of your buddies comes up behind you and hits the welding table with a big hammer. If you just keep welding without flinching, you’re a welder. Strive to pass the test.
That brings up the second point, focus. All forms of manual welding, oxy-acetylene, stick, MIG, and TIG require focus, to get results. You have to keep a sharp eye on the weld puddle and learn to read how it is behaving. If you practice, you can actually see the metal moving around in the puddle as it flows. That’s the kind of focus I mean.
Any kind of distraction, pain, noise, even coffee can affect your focus. If you are in a noisy place, wear some ear protection. Lack of comfort leads to pain, pain leads to distraction, and that leads to a bad weld puddle because you can’t focus.
Maximizing focus takes time and practice. I had a year of stick welding at a vocational school before I was steady enough to successfully weld overhead butt joints. And, that’s after a couple of years of oxy-acetylene welding sheet metal parts for my automotive projects. That’s one reason I recommended standard sized gas bottles, especially if you are just learning to weld. You need to practice and standard bottles will give you a lot of time behind the torch.
Practice and focus are key elements to a clean bead, regardless of the welding process you are using.
The standard movement for running a flat bead is a circular motion about 3/8 to ½ inch in diameter, using a small to medium sized torch. For thin stock, like 1/8 inch mild steel, it’s best to just let the inner blue flame touch the metal at a 30 degree angle.
You’ll have to watch the metal while it heats up. It should start to glow red, but not bright orange or white. At some point the metal will become molten and you can continue the little circles while moving to the left. I’m right handed so generally I position the work so I start on the right and move to the left. Obviously, that’s not always possible, but we try. Don’t forget the first rule of being comfortable.
As you move the torch in the little circles, to the left, you can vary the speed of the circles, move the blue flame tip closer or further from the work, and vary the speed of movement across part. The effects of all of these subtle changes can be clearly seen with a clean set of goggles and focus. I remember times when I’d be intensely watching the weld puddle and noticed that my face was only about a foot away from the puddle. Needless to say, you s might want to wear one of those cool canvas welding hats to keep from burning up the old mop, if you know what I mean.
Coordinating your hand to what you see will again, take time and practice. Too long in one spot and the metal will melt through causing a whole. Not long enough in one spot and you don’t get enough penetration for a strong seam. It’s a balancing act that requires focus and the right touch.
Weld A Bead
Put a flat piece of steel on the table and heat up a puddle. While still doing the little circles move the torch smoothly in one direction, taking the puddle along with your movement. Play with the angle and distance you keep the inner blue flame away from the puddle to see how it reacts.
When first starting out, you don’t even need any filler rod, so just practice with the torch.
When you get to the end of a bead, slowly lift the torch tip, so the puddle solidifies, without any craters.
We’ve discussed how to run a bead. It takes practice, focus, and patience. Remember to be comfortable and work on that eye-hand coordination.