Figure 7-12.Comparison chart of welds.
Figure 7-13.Undercuts and overlaps in welding.
Length of Arc
When an arc is too long, the metal melts off the
electrode in large globules and the arc may break fre-
quently. This produces a wide, spattered, and irregular
deposit with insufficient fusion between the base metal
and the weld (fig. 7-12, view F).
When an arc is too short, it fails to generate enough
heat to melt the base metal properly, causes the electrode
Figure 7-14.Setting the length of an arc.
to stick frequently to the base metal, and produces
uneven deposits with irregular ripples. The recom-
mended length of the arc is equal to the diameter of the
bare end of the electrode, as shown in figure 7-14.
The length of the arc depends upon the type of
electrode and the type of welding being done; therefore,
for smaller diameter electrodes, a shorter arc is neces-
sary than for larger electrodes. Remember: the length of
the arc should be about equal to the diameter of the bare
electrode except when welding in the vertical or over-
head position. In either position, a shorter arc is desir-
able because it gives better control of the molten puddle
and prevents atmospherical impurities from entering the