Longevity TIGWELD 250 EX Operating Manual page 20

TIGWELD® 250 EX
Length of Arc When an arc is too long, the metal
melts off the electrode in large globules and the arc may break frequently. This produces a wide,
spattered, and irregular deposit with insufficient fusion between the base metal and the weld.
When an arc is too short, it fails to generate enough heat to melt the base metal properly, causes
the electrode
Fig. 3
Setting the length of an arc to stick frequently to the base
metal, and produces uneven deposits with irregular ripples. The recommended length of the arc
is equal to the diameter of the bare end of the electrode, as shown in figure 3.
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 necessary 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
desirable because it gives better control of the molten puddle and prevents atmospherical
impurities from entering the weld.
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