Stick welding amperage chart by rod size
The right amperage depends mainly on three things: the rod diameter, the metal thickness and the position you are welding in. This chart gives you the starting point. The fine tuning you do by listening to the arc and reading the bead.
3/32 in (2.4 mm) rod: 60 to 90 A. 1/8 in (3.2 mm) rod: 90 to 130 A. 5/32 in (4.0 mm) rod: 130 to 180 A. These are flat-position values for mild steel. Vertical and overhead: drop 10 to 15%.
Amperage by rod diameter
Start in the middle of the range, then adjust. The package label lists the range and the polarity the maker recommends, and it has the last word.
| Rod diameter | Flat position | Vertical / overhead | Typical plate* |
|---|---|---|---|
| 5/64 in (2.0 mm) | 45–70 A | 10 to 15% lower | 1/16–3/32 in (1.6–2.4 mm) |
| 3/32 in (2.4 mm) | 60–90 A | 10 to 15% lower | 5/64–5/32 in (2–4 mm) |
| 1/8 in (3.2 mm) | 90–130 A | 10 to 15% lower | 1/8–1/4 in (3.2–6.4 mm) |
| 5/32 in (4.0 mm) | 130–180 A | 10 to 15% lower | 3/16–3/8 in (4.8–9.5 mm) |
| 3/16 in (4.8 mm) | 180–230 A | 15 to 20% lower | 5/16 in (8 mm) and up |
Currents: Table 3.2 of the e-book The Welder's Forge (mild steel). Starting point: confirm with the rod package, the WPS or the machine manual. *Plate thickness is practical guidance; thick plate takes several passes.
How to set the machine, step by step
- Start mid-range. With a 1/8 in (3.2 mm) rod, begin around 100–110 A.
- Run a test bead on a scrap of the same plate, in the same position as the real job.
- Listen to the arc. A stable arc makes a steady crackle, like bacon frying in a pan. If it pops and goes out, something is off.
- Read the bead and adjust in 5 A steps, using the signs below.
- Check the rod package: the maker lists the range and the polarity.
Signs of too much current
- Heavy spatter and an aggressive arc.
- Undercut: a groove along the toe of the bead.
- Burn-through on thin plate.
- The rod glowing red before it is half used.
Signs of too little current
- The rod sticks to the work when you strike the arc. If that is your problem, see welding rod sticking to the metal.
- An unstable arc that keeps going out.
- A tall, narrow bead sitting on top of the plate without fusing the edges.
- Slag that is hard to remove.
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Before touching the amperage dial, check the work clamp (the ground clamp). A clamp far from the joint, or clamped over paint and rust, makes the arc unstable and looks exactly like the wrong current.
Out of position: why you lower the current
Vertical and overhead, the pool wants to fall. Less current gives a smaller pool that is easier to control. Example: if you run 110 A on a 1/8 in (3.2 mm) rod in the flat position, start near 95 A on a vertical joint. The full technique is in vertical stick welding.
Does 120 V or 240 V change the chart?
No: the reference current depends on the rod, not on the outlet. What changes is what the machine can deliver. Many dual-voltage inverters have a lower maximum output on 120 V, so read the nameplate and the manual before counting on a 5/32 in (4.0 mm) rod. Machine dials are not always accurate either, which is one more reason this chart is a starting point and not a guarantee.
What about 6013 and 7018 amperage?
The chart serves as a reference for the most common mild steel rods. The E6013 (rutile) is the easiest and forgives the most; the E7018 (low-hydrogen) wants a shorter arc and has its own storage rules. The differences are in 6013 vs 7018.
What about thin sheet and tubing?
Below about 14 gauge (.075 in, 1.9 mm), the margin between “did not fuse” and “burned through” is small. Use the smallest rod you have, stay at the low end of the range, make short tacks and alternate sides so heat does not pile up in one spot. On car body sheet, MIG is usually easier. The details are in welding thin sheet metal without burning through.
Change the amperage with the rod out of the electrode holder, and wear a helmet with the right shade (shade 10–11 up to about 160 A, Table 2.1 of the e-book). Keep clear of flammables within 35 ft (11 m) or cover them, and keep your gloves dry: the open-circuit voltage of a stick machine is enough for a serious shock.
Frequently asked questions
What is the amperage for a 3/32 in (2.4 mm) rod?
What is the amperage for a 1/8 in (3.2 mm) rod?
Why does my rod stick to the plate?
Is the amperage the same on an inverter and an old transformer machine?
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