7018 Rod Sticking During Restarts: Causes and Fixes

When a 7018 rod sticks during restarts, the usual problem is not the rod alone. It is usually a combination of a cold restart, heavy crater slag, poor restart prep, arc length too short, low amperage, weak work lead contact, or damp low-hydrogen electrodes. A 7018 electrode needs a clean restart point and enough current to re-establish the arc without burying the rod tip into frozen slag or unmelted metal.

Common Symptoms

• Rod freezes to the crater as soon as the arc is struck.
• Restart piles up instead of tying into the previous bead.
• Slag traps at the restart toe or centerline.
• Arc starts, flashes, then goes out.
• Electrode end turns black or balls over after repeated sticking.

Likely Causes

• Amperage too low: 7018 is a low-hydrogen, iron-powder electrode with medium penetration. If the current is low, the restart area will not wet in quickly.
• Restart not cleaned: 7018 slag must be chipped and brushed before welding over it. Even a thin glassy film can hold the rod off the base metal and create inclusion.
• Arc length too tight: Dragging the rod hard into the crater can extinguish the arc and freeze the electrode.
• Wrong polarity or weak output: Standard E7018 is commonly run AC or DCEP depending on rod and machine. Wrong polarity, undersized leads, poor clamp contact, or long extension cords can make restarts sluggish.
• Moisture exposure: Low-hydrogen rods that have been left open too long may restart poorly and increase hydrogen cracking risk on critical work.

Inspection Steps

1. Chip the crater completely and wire brush until the restart point is metallic, not dull gray slag.
2. Check the work clamp on clean steel, not paint, rust, mill scale, or a loose table slot.
3. Verify rod diameter and amperage. A 1/8 in. 7018 commonly runs around the 90–140 amp range depending on brand, position, and joint.
4. Confirm polarity required by the actual electrode container.
5. Inspect the rod end. If flux is broken back unevenly, restrike on scrap or break the end clean before restarting.

Restart Technique

Start slightly ahead of the crater, establish the arc, then move back into the crater long enough to remelt the end of the previous bead. After the puddle wets into both sides, continue forward. Do not start directly in a slag pocket. Do not stab the rod into the crater. Keep a short but live arc and watch the puddle edge, not the arc flare.

Field Fix vs Proper Fix

Field fix: turn amperage up 5–10 amps, clean the crater harder, and restrike on scrap before the restart. Proper fix: correct polarity, clamp contact, rod storage, joint prep, and restart technique. On code work, grind defective restarts out instead of burying them.

Safety Notes

Stuck electrodes are live electrical faults. Do not twist a stuck rod loose with bare gloves or exposed skin near grounded work. Break the electrode free safely, inspect the holder, and replace damaged stubs. Use proper welding PPE and ventilation.