[dfarning]

I am sorry if this is obvious... as part of my 'learning to mig weld' I try to run a 3 inch by 3 inch pad of beads four layers thick each evening. For now, I am doing these in the flat position until they become second nature.

I am shooting for beads about 1/4 inch wide to develop consistency. Should I start practicing thinner beads to prepare for working on thin material or will running thin beads on my thick pad just encourage bad habits?

[jwright650]

Travel speed generally dictates the size for a given machine setting, but...if you keep things consistent, you can manipulate the shape of the bead a couple of ways. First, more voltage will flatten the bead(make the puddle watery to that it flatten out), while more WFS(amps) will make it pile up and stand taller. But there are limitations with this....too much WFS and the bead can roll over on the toes and not wet in as well or start producing a large quantity of spatter. Too much voltage and the wire can burn back into the tip....so you have to find the balance between volts and WFS(amps) settings.

[weldin mike 27]

Judge your travel speed on going as slow as you can but still keeping the arc on the front of the puddle (is burning into fresh metal) if you are pushing the gun.

[dfarning]

Thanks guys,

I will get out drill bits of various sizes to use as gauges and then experiment with my machine and travel speed until I can consistently make beads of various sizes.

I feel like a moth... I try to watch the puddle but my focus keeps getting pulled back to the bright light.

David

[weldin mike 27]

Arc mesmerization. Its pretty common.

[dfarning]

But there are limitations with this....too much WFS and the bead can roll over on the toes and not wet in as well

Is this what it is called when the puddle seems to be forming very quickly from the filler wire and just seem to be sitting on top of the base metal rather than melting in.

David

[Otto Nobedder]

But there are limitations with this....too much WFS and the bead can roll over on the toes and not wet in as well

Is this what it is called when the puddle seems to be forming very quickly from the filler wire and just seem to be sitting on top of the base metal rather than melting in.

David

Yep. I typically call it "cold-lap", where the amount of metal deposited won't lay in the weld zone. A "fat" bead that hangs over, like a fat man's belly over his belt. Not enough heat for the base metal. Counterintuitively, you should turn the machine down. Power transfer is a function of voltage, current, and resistance. Voltage is a set quantitiy on a MIG, and current is adjusted with the wire speed. Resistance is a function of many things including arc-length (stick-out), and the temperature of the puddle.

Backing the machine off to, say, 18.5V and 210IPM (these figures for .035 wire) will slow everything down for you, and let you see what's happening.

Steve S