Weld weaving and whipping: Negatives to consider

Q: When using GMAW on carbon steel materials 1/8 inch thick or greater, we use a whipping technique that you have described as a bad work habit. What are the negative effects of whipping or weaving?

A: As with many welding techniques, there is a time and place for everything, even whipping and weaving for GMAW. For example, most robotic applications use a constant weaving motion from side to side, and pipefitters use a distinct whipping action (fore and aft) when laying a 6010 root pass. These movements are perfectly acceptable for those applications—the robot uses the motion to find its way, and the pipefitter uses the fast-freeze characteristic to burn away the land and place the root perfectly at each whip.

In production GMAW, however, these same techniques can have negative effects on your finished product.

Negative Effects of Weaving

Weaving with GMAW is a common technique when welding vertical-up, because it can be difficult to carry the puddle up without it. A slight weave is common when using GMAW in other positions, but it should be no more than 2.5 times the electrode (wire) diameter—for a 0.035-in.-dia.-wire, that comes to about 1/8 in. of movement. Exceeding that value can lead to overlap, undercut, and other undesired conditions. Multiple stringer passes should be considered when additional bead width is needed.

Negative Effects of Whipping

Sometimes whipping is used to bridge a gap, but you would be better off turning down the power source to a short-circuit transfer and applying that root. Again, a slight whip is common, but should be no more than 1.5 times the wire diameter. If the key to quality GMAW is keeping the arc on the leading edge of the puddle, then the whip technique goes against that.

Excessive whip can undersize weld throats and increase weld spatter because each time you back the arc away from the leading edge, you are driving the wire into the molten metal.