This term refers to an obsolete electrode which was lightly coated with an arc-stabilizing chemical. This coating might simply have been the lime retained from
the lubricant used in the drawing operation, or a light rust coating which formed on the electrode after it was drawn.
These electrodes were more commonly used when arc welding electrodes were initially introduced. The coating of a dust-coated electrode did not affect the character of deposited weld metal, but served to produce more uniform arc characteristics than those
obtained with bare wire. The dust coating did not affect the prevention of oxidation, and no slag was formed on the weld bead. See ELECTRODE MANUFACTURE, Historical Background.