Flux-Core Welding Positions: Flat, Vertical, Horizontal, and Overhead FCAW

Flux-cored arc welding works in all four standard positions: flat (1G/1F), horizontal (2G/2F), vertical-up (3G/3F), and overhead (4G/4F). The process handles out-of-position work well because the slag system supports the molten weld pool against gravity. Wire selection, parameter adjustments, and technique changes for each position determine whether you get a sound weld or a mess of drips and slag inclusions.

E71T-11, E71T-8 (self-shielded), and E71T-1 (gas-shielded) are all classified for all-position welding. The “1” in the second digit of each classification indicates all-position capability. Wires with a “0” in that position (E70T-1, E70T-5) are restricted to flat and horizontal only.

Flat Position (1G/1F)

Flat position is the easiest and most productive position for FCAW. Gravity holds the weld pool in the joint, the slag floats to the surface naturally, and you can run at the highest wire feed speeds and travel speeds.

Settings

Use the upper end of your parameter range. For 0.045" E71T-1 gas-shielded on 1/4" plate:

• Voltage: 25-27V
• Wire speed: 250-300 IPM
• Travel speed: 12-18 IPM
• Stick-out: 3/4" to 1"

For 0.045" E71T-11 self-shielded on 1/4" plate:

• Voltage: 19-21V
• Wire speed: 220-270 IPM
• Travel speed: 10-14 IPM
• Stick-out: 3/4" to 1"

Technique

Run stringer beads or moderate weaves (up to 3/4" wide for 0.045" wire). Drag angle of 15-20 degrees (gun tilted back from the direction of travel). Travel speed is steady and consistent. The bead should have a slightly convex profile with smooth, well-fused toes.

Flat position is where FCAW deposition rate advantages show most. With 1/16" E71T-1 gas-shielded wire, deposition rates of 12-20 lbs/hour are achievable. This makes flat-position FCAW the fastest semi-automatic welding process for heavy steel. For detailed settings, see flux-core welding settings.

Horizontal Position (2G/2F)

Horizontal welding places the weld axis horizontal with the face of the weld roughly vertical. Gravity tries to pull the puddle downward, causing the top toe to undercut and the bottom toe to build up (overlap).

Settings

Reduce wire feed speed 5-10% below flat settings. Keep voltage at the low-to-mid range. For 0.045" E71T-1 on 1/4" plate, horizontal:

• Voltage: 24-26V
• Wire speed: 230-280 IPM
• Travel speed: 10-14 IPM
• Stick-out: 3/4"

Technique

Gun angle: Tilt the gun 5-10 degrees upward from perpendicular (pointing slightly above the horizontal plane of the joint). This directs the arc force and puddle deposition toward the upper toe, counteracting gravity’s pull downward.

Work angle: Aim the wire at the upper plate (the vertical member on a T-joint) more than the lower plate. The arc digs into the upper plate while gravity helps the puddle fuse to the lower plate.

Travel technique: Use a straight drag technique or a very slight weave with a pause at the upper toe. Pausing at the top lets the puddle wet into that corner before moving on. Don’t weave so wide that the puddle sags.

Multi-pass horizontal fillets: For fillet welds larger than single-pass capability (roughly 5/16" leg for 0.045" wire), stack passes. Put the first pass in the root with a stringer. Stack subsequent passes on top, each offset slightly toward the upper plate. The shelf of previous passes supports the next one.

Common Horizontal Problems

• Undercut on the upper toe: Too much heat, too fast travel, or the gun is angled too far downward. Slow down and angle the gun more toward the upper plate.
• Overlap on the lower toe: The puddle sags and solidifies over the lower plate without fusing. Reduce heat, increase travel speed, or adjust gun angle upward.
• Convex bead profile: Voltage too low. The puddle piles up instead of wetting out. Increase voltage 0.5-1V.

Vertical-Up Position (3G/3F)

Vertical-up welding fights gravity directly. The molten pool wants to run down the joint. FCAW’s fast-freeze slag supports the puddle, making vertical-up welding more manageable with flux-core than with solid MIG wire. Structural welding codes require vertical-up for most applications because it produces better penetration and fusion than vertical-down.

Settings

Reduce wire feed speed 10-15% below flat settings. Drop voltage 1-2V. For 0.045" E71T-1 on 1/4" plate, vertical-up:

• Voltage: 23-25V
• Wire speed: 200-250 IPM
• Travel speed: 4-7 IPM (much slower than flat)
• Stick-out: 3/4"

For 0.045" E71T-11 self-shielded, vertical-up:

• Voltage: 17-19V
• Wire speed: 180-230 IPM
• Travel speed: 4-6 IPM
• Stick-out: 3/4"

Technique

Start at the bottom. Always weld uphill, starting at the bottom of the joint and traveling up. The solidified weld metal below acts as a shelf that supports the next increment of molten pool.

Gun angle: Point slightly upward, 5-15 degrees from perpendicular to the plate surface. The arc pushes down into the shelf while you build upward.

Weave pattern: Most vertical-up FCAW uses a weave pattern rather than a stringer:

• Triangle weave: Move the gun in a triangular pattern: up the center, pause at one toe, across to the other toe, pause, then back to center and up. Each pause at the toes allows the puddle to wet into the sidewall.
• Z-weave (zigzag): Move across the joint in a zigzag with brief pauses at each toe. Simpler than the triangle but can leave a slight concavity in the center.
• Straight stringer: Some welders prefer stringer beads on narrow groove welds. Slower travel speed compensates for the lack of weave.

Pause at the toes. This is the single most important vertical-up technique. The brief hesitation (about 1 second) at each sidewall lets the puddle fuse into the base metal. Without the pause, the weld rolls over the toes without penetrating.

Don’t watch the arc. Watch the puddle behind the arc. If it’s getting too large and starting to drip, you’re too hot or moving too slowly. Speed up slightly or reduce wire speed.

Shelf Building

The key concept in vertical-up FCAW is building a shelf. Each weave cycle deposits a small increment of weld metal that solidifies into a ledge. The next cycle deposits on top of that ledge. The slag solidifies quickly and helps hold the pool.

If the shelf collapses (the puddle drips), you have too much heat. Stop, let the area cool briefly, and restart with lower parameters. A common beginner mistake is trying to push through a dripping puddle by going faster. You can’t outrun gravity. Reduce heat first.

Vertical-Down Position

Vertical-down welding moves downhill, from top to bottom. It’s faster than vertical-up but produces shallower penetration and higher risk of slag inclusions (the slag can run ahead of the puddle and get trapped).

Limited applications: Vertical-down is only acceptable for non-structural and non-code work on thin material (typically 3/16" or less). AWS D1.1 does not allow vertical-down welding for most structural connections unless specifically qualified by procedure.

Wire selection: E71T-GS self-shielded wire handles vertical-down on thin material. Most E71T-11 and E71T-1 wires are not designed for vertical-down.

Technique: Run fast with a drag angle of 20-30 degrees pointing downward. The bead should be thin and flat. If slag runs ahead of the puddle, you’re moving too slowly.

Overhead Position (4G/4F)

Overhead welding is the most demanding position. The weld pool hangs directly above you, and any excess heat causes it to drip. FCAW handles overhead better than many welders expect because the fast-freeze slag supports the pool.

Settings

Reduce wire feed speed 10-15% below flat settings. Drop voltage 1-2V. For 0.045" E71T-1 on 1/4" plate, overhead:

• Voltage: 23-25V
• Wire speed: 200-240 IPM
• Travel speed: 8-12 IPM
• Stick-out: 5/8" to 3/4"

For 0.045" E71T-11 self-shielded, overhead:

• Voltage: 17-19V
• Wire speed: 180-220 IPM
• Travel speed: 7-10 IPM
• Stick-out: 5/8" to 3/4"

Technique

Stringer beads only. Do not weave in overhead position with FCAW unless you’re very experienced. Wide weave patterns let the puddle grow too large and drip. Stringer beads keep the puddle small and controllable.

Short stick-out. Reduce stick-out to 5/8"-3/4" to keep the arc tight and concentrated. Longer stick-out in overhead position leads to a wandering arc and dripping puddle.

Consistent travel speed. Don’t slow down or stop. Hesitation lets the puddle grow, and a large overhead puddle drips. Move at a steady pace that keeps a small, manageable puddle.

Gun angle: Slight drag angle, 10-15 degrees from perpendicular. Keep the gun close to perpendicular to avoid directing the arc force sideways.

Multi-pass overhead: Build up with narrow stringer passes side by side. Overlap each pass by about 30-50% of the previous bead width. Clean slag completely between passes. The shelf effect works in overhead too: each solidified pass provides a surface for the next one.

Overhead Safety

Gravity delivers spatter, slag chips, and occasional metal drips straight to you. Full protective gear is mandatory:

• Leather jacket or flame-resistant coveralls (not just a shop apron)
• Leather welding cap under the helmet
• Button collar closed, no exposed skin at the neck
• Leather gloves with gauntlet cuffs that overlap sleeves
• Safety glasses under the welding helmet

Wire Selection by Position

Troubleshooting Position-Specific Problems

Weld drips in vertical-up: Too much heat. Reduce wire speed 10-15%, drop voltage 1V, or increase travel speed. If it still drips, the ambient temperature may be pre-heating the joint (from previous passes or nearby welding). Let it cool below interpass maximum before continuing.

Slag runs ahead of the puddle (vertical-up): Travel speed too slow. The slag has time to flow down over unwelded metal, trapping it under the next bead. Increase travel speed. The arc should always be ahead of the slag.

Undercut on overhead welds: Travel speed too slow, allowing the arc to dig into the base metal while the puddle sags away. Increase travel speed or reduce wire speed. A slightly shorter stick-out also helps concentrate the arc.

Inconsistent bead width in any position: Stick-out is changing during the weld. This is especially common in overhead and vertical where your body position is uncomfortable. Brace your arms or body against the workpiece and focus on maintaining consistent gun distance.

Porosity in overhead or vertical: Stick-out too long (reducing shielding effectiveness), contamination on the base metal, or moisture in the wire. Shorten stick-out, clean the joint, and check wire storage. For gas-shielded wire, also check gas flow and nozzle for spatter blockage.

For additional troubleshooting of spatter issues across all positions, see flux-core spatter reduction.