Vertical and Overhead Wire Welding Technique

Flat welding lets gravity help you. Out of position, gravity works against you, and molten metal wants to fall out of the joint. Most real fabrication has welds you cannot turn flat: a column splice, a frame locked in a jig, a repair under a machine. A good mid-level welder can hold a small, controlled puddle on a wall or a ceiling and knows which wire and settings make that possible. You should already be able to run a sound flat bead with MIG and flux-cored wire.

What You Will Be Able to Do

• Pick a process, transfer mode and wire that can weld in the position you need.
• Set up for a smaller puddle using the wire maker's all-position data.
• Run vertical-up fillets and grooves with the right motion.
• Weld overhead with stringers, and protect yourself from falling spatter.
• Use travel speed to check that you are not overwelding.

Why Position Changes the Job

A reminder on the codes: the number gives the position and the letter gives the weld type. So 3F is a vertical fillet, 3G is a vertical groove, 4F is an overhead fillet and 4G is an overhead groove.

Surface tension holds a small puddle in place, the same way a drop of water hangs from a faucet. A big puddle is too heavy for that, and it sags or drips. You have two ways to win:

• Make the puddle smaller. Use less heat and less metal per inch.
• Make it freeze faster. Use a wire with a fast-freezing slag, which acts like a dam under the molten metal.

Everything else in this work comes back to those two ideas. If a weld is sagging, the puddle is too big or too hot for that position.

Choosing a Process That Can Do It

Not every setup can weld out of position. Check this before you spend time on technique.

Short-circuit MIG deserves a warning. It handles position well because it runs cool, and that same cool arc can lay metal on top of thick steel without fusing it. Under AWS D1.1, short-circuit MIG is not one of the prequalified processes, so structural work with it needs a procedure proven by testing. On thick material out of position, flux-cored wire or pulsed MIG is usually the better choice, if your Welding Procedure Specification (WPS) allows it.

Setting Up for a Smaller Puddle

As a starting point, Miller Electric suggests running voltage and amperage about 10 to 15 percent below your flat settings for the same weld. A better source is the wire maker's data sheet, because many list separate ranges for all-position and flat work.

Here is what one maker publishes for one 0.045 inch E71T-1 wire on CO2. That maker says to drop about 1 volt on 75/25 argon-CO2.

Notice the gap. The all-position range tops out well below the flat range. If you carry your flat settings up a wall, you will have a puddle far too big to hold. Use the numbers for your own wire, and stay inside your WPS when you have one.

Run a test on scrap of the same thickness, in the real position. A test bead on a bench proves nothing about a wall.

Vertical Up

Vertical up means you start at the bottom and travel upward. It gives more heat and better penetration than going down, and it is the normal direction for code structural work.

1. Set your body first. Stand or sit so you can reach the whole weld without shifting your feet. Do a dry run with the arc off.
2. Set the gun nearly square to the plate. Sources give a travel angle of about 5 to 15 degrees off square, and one wire maker says its E71T-1 wires often run best at close to zero. Start square and adjust from the bead. The usual flux-core drag angle does not carry over directly to this position.
3. Split the joint. On a tee joint, hold about 45 degrees between the plates so that both get equal heat.
4. Build a shelf. Start at the bottom and let the first bit of metal start to freeze. Each new layer then sits on the shelf below it.
5. Use a small motion. A slight zigzag or a small triangle works. Pause at each toe and move quickly across the face. The pause fills the toe, and the quick crossing keeps the center from building up.
6. Keep the arc on the leading edge. The arc must stay on the top edge of the puddle. If the puddle gets ahead, you are laying metal on cold steel.
7. Fill the crater. Slow down at the top and let the end fill before you release the trigger.

Keep the weave narrow and follow any limit your WPS sets. A wide weave adds heat and can trap slag at the toes.

Reading a Vertical Bead

Worked Example: Is Your Travel Speed Right?

You are welding a 5/16 inch vertical-up fillet in 3F with the 0.045 inch wire above. You use 185 amps. The data sheet lists a deposition rate of 6.1 pounds an hour at that setting. Deposition rate is how much weld metal the wire lays down while the arc is on.

Step 1: Metal needed per foot. A flat-faced fillet is a triangle, so its area is leg x leg divided by 2.

• Area: 0.3125 x 0.3125 / 2 = 0.049 square inch
• Volume per foot: 0.049 x 12 = 0.586 cubic inch
• Weight per foot: 0.586 x 0.283 pound per cubic inch of steel = 0.166 pound

Step 2: Speed.

• 6.1 / 0.166 = about 37 feet an hour
• 37 x 12 / 60 = about 7.4 inches a minute
• One foot of weld takes about 98 seconds

Real welds carry a little extra crown, so you may run slightly slower. If a foot is taking you 3 minutes, though, you are traveling at 4 inches a minute and laying down almost twice the metal the weld needs. That extra metal costs time and wire, adds distortion, and makes the bead harder to hold on the wall.

Vertical Down

Vertical down means you start at the top and travel down. It runs fast and shallow. It has a place on thin sheet, where vertical up would burn through, and some self-shielded wires are made for certain downhill work.

The risk is the puddle. If it runs ahead of the arc, the metal lies on the plate without fusing, and the bead can look fine while it does. Keep the arc on the leading edge and travel fast enough to stay ahead of the puddle. Only weld downhill where your WPS or shop procedure allows it. Direction is commonly an essential variable, so going downhill on an uphill procedure can make a good-looking weld nonconforming.

Overhead

Overhead has the least help from gravity, so the rules get stricter.

1. Use stringers. Run straight beads with little or no weave. Small beads freeze before they can fall.
2. Keep the heat down. Stay at the low end of the all-position range.
3. Hold a short, steady stickout. A wandering stickout changes your heat, and overhead you have no room for that.
4. Stand to the side. Do not put your head under the arc. You want spatter and fume to miss you.
5. Keep your travel moving. Stopping lets the puddle grow, and it will drop.
6. Clean the nozzle often. Spatter falls straight into it overhead and chokes the gas flow.
7. Clean every pass. On multi-pass work, chip all slag. Overlap each stringer on the one before it, and make sure each new bead ties into the sidewall.

Warning: Falling spatter finds every opening. Wear a leather jacket or sleeves, a welding cap, and earplugs or ear covers. Button your collar and cuffs, and do not wear pant cuffs or pockets that can catch hot metal. Burns inside the ear canal are a real overhead injury.

Working in Awkward Spots

Skill matters less than setup when you cannot get comfortable. A few habits help:

• Do a dry run every time. Trace the full weld with the gun and the arc off. If the cable snags halfway, fix it now.
• Support the cable. Drape it over your shoulder or a hook, so that its weight does not pull your hand. Sharp bends in the cable also make the wire feed stutter.
• Brace your body. Lean on the work or a stand with your arm or shoulder, using dry leathers.
• Plan your stops. If you cannot finish in one pass, stop where you can restart cleanly. Grind out a bad crater before you tie in.
• Control the fume. A plume rises past your face on a vertical weld. Position your local exhaust or fume gun, and keep your head out of the plume.
• Work from a safe platform. Use proper scaffolding, a lift or a stand. Do not balance on the work. Above the height your site sets, you need fall protection and the training that goes with it.

Common Mistakes

• Running flat settings on a wall. The puddle sags, and the weld fails on profile or size.
• Grabbing an E70T wire for vertical work. A wire with a 0 in that spot is rated flat and horizontal only.
• Weaving wide to fill faster. You get slag at the toes and too much heat.
• Trusting short-circuit MIG on thick plate. The bead can look smooth and still sit on top of the steel.
• Testing on a bench. Your settings have to be proven in the position you will weld.
• Skipping ear protection overhead. One drop of spatter can mean a trip to the doctor.

Check Your Understanding

You move from a flat fillet at 260 amps to the same size fillet in 3F, and the bead sags badly. You have changed nothing else. What is wrong?

You are running flat settings in the vertical position. Drop to the wire's all-position range, stay inside your WPS, and test on scrap in the real position.

A coworker hands you a spool marked E70T-1 for an overhead weld. What do you tell them?

That wire is rated for flat and horizontal only, because of the 0. You need an all-position wire such as E71T-1, and the wire has to match your WPS.

Your vertical-up fillet has a good face, but both toes show a small groove. What do you change first?

Pause longer at each toe and lower the voltage slightly. Those grooves are undercut, so the toes are not being filled before you move on.

A foot of 1/4 inch fillet should take about 1 minute at your settings, and yours are taking almost 2 minutes. Why does that matter if the weld looks fine?

You are laying down about twice the metal. It costs time and wire, adds heat and distortion, and may push the weld over its size limit.

Key Takeaways

• Out of position, keep the puddle small and let it freeze quickly.
• Check that the process and wire can weld in that position before you start.
• Use the wire's all-position data, not your flat settings, and stay inside your WPS.
• Vertical up uses a shelf, a small motion, and a pause at each toe.
• Overhead uses stringers, low heat and full protection from falling spatter.
• Travel speed is a check on weld size, so time your welds.