A ropey bead
High, narrow, lumpy, and sitting on the plate instead of joined to it.
The short answer. A ropey bead is metal that froze before it could flow out. That's either not enough heat or too much wire, and it's very often both at once because the two knobs fight each other. Turn the heat up before you slow down — most people reach for travel speed first and make the profile worse.
What it looks like
The bead stands proud and rounded, narrower than it should be for the amount of metal in it, with ripples that are coarse, widely spaced and often irregular. The name is literal: it looks like a length of rope laid on the plate.
The critical detail is at the edges. On a good bead the metal wets out — it flows onto the parent plate and meets it at a shallow, smooth angle you can run a fingernail across without catching. On a ropey bead the metal meets the plate at a steep angle, often close to 90°, sometimes rolling over the top of it without fusing at all. That steep transition is called a high reinforcement angle, and it's a much better indicator of a problem than the ripples are.
If the metal has actually rolled over onto unfused plate, that's overlap (or cold lap) — a genuine defect rather than just an ugly profile, and one that codes treat seriously because there is no bond at all under that lip.
What causes it
Voltage too low (MIG)
Voltage controls how the arc spreads and how the bead flattens out. Too little and the puddle stays balled up and freezes before it can wet the toes. If your bead is ropey and you're also getting a harsh, spitting, stuttering arc sound rather than a steady crackle, voltage is almost certainly your problem. Turn it up in small steps until the bead flattens and the sound smooths out.
Wire feed speed too high (MIG)
The other half of the same problem. Too much wire for the voltage means more metal arriving per second than the arc can melt and spread, so it piles up. You may also feel the wire stubbing into the plate and pushing the gun back at you. Wire speed and voltage have to be balanced — changing one alone just moves you along a different edge of the same envelope.
Amperage too low (stick and flux-core)
Same principle, one knob. Not enough current means a puddle that's too small and too cold to flow, so it heaps. With 7018 in particular, a rod run too cold gives a high, narrow bead with slag that fights you and clings in the toes rather than lifting off cleanly. If your slag is hard to remove, that's a heat message, not a slag problem.
Travel speed too slow
Counter-intuitive, but real: moving too slowly piles more metal into a given length of joint than that joint can take. The puddle grows, gets ahead of the arc, and you end up depositing onto metal that the arc is no longer heating — so it sits on top rather than fusing in. The tell is a bead that is both ropey and unusually wide and tall for the plate.
The plate is too cold
On thick section, in a cold workshop, or first thing on a winter morning, the parent metal draws heat out of the puddle fast enough to freeze it early even with correct settings. Thick material may genuinely need preheat, and that requirement comes from the procedure for the material — not from how the bead happens to look.
How to work out which one is yours
- Ropey, narrow, harsh spitting arc (MIG) — voltage is too low. Raise it first.
- Ropey with the gun being pushed back at you (MIG) — wire speed too high for the voltage.
- Ropey, narrow, stubborn slag (stick/flux-core) — amperage too low.
- Ropey and unusually wide/tall — you're travelling too slowly.
- Ropey only on thick plate, fine on thin — heat is going into the parent metal. Check whether the procedure calls for preheat.
- A visible lip rolled over unfused plate — that's overlap. Treat it as a defect to be removed, not a cosmetic issue.
Ripples, and the thing people get wrong about them
Coarse ripples are a symptom worth reading, but the "stack of dimes" appearance is not itself a measure of weld quality — a point argued at length in every welding forum that has ever existed, and correctly. Fine, evenly spaced ripples usually indicate steady travel and a well-behaved puddle, which is why they correlate with good welds. Correlate. A dead-consistent ripple pattern laid over unfused plate is still a bad weld, and a slightly irregular bead that has genuinely fused is a good one.
So: use ripple consistency as evidence about your hand speed, which is what it actually measures. Judge the weld on wetting, profile and fusion.
What a photo can and can't tell you
Bead profile photographs well. Height, width, the angle where the bead meets the plate, and ripple spacing are all genuinely visible from above with decent light and something in frame for scale — and the reinforcement angle in particular is a strong, honest indicator that a photo can assess.
What it cannot see is whether the metal actually fused, and that's the entire point of a ropey bead. Overlap and lack of fusion both live at the boundary between the bead and the plate, and from above, a bead that has fused beautifully and one that is merely resting there can look near-identical. That boundary is what a bend test or an ultrasonic inspection is for. Surface visual only — internal defects need RT/UT and a qualified inspector.
Related
- Running too cold — the underlying condition, and its more dangerous form.
- Running too hot — what over-correcting looks like.
- Undercut — what you get if you fix ropiness with travel speed alone.