Slag forms over a stick weld bead as the protective coating of the stick electrode melts. The slag protects the molten weld from contamination from air in the atmosphere. Removing the slag from a cooled weld exposes the finished weld. This allows you to paint the weld or make another weld pass over the cleaned bead. The glass-like slag removes easily with the proper tools. Using the wrong tools can damage the surface of the weld bead and reduce its strength.
Tap along the stick weld bead with the flat beveled end of weld chipping hammer to remove large portions of slag from the weld's surface. Turn over the hammer and chip smaller portions of slag from the weld with the sharp pointed end of the chipping hammer.
Align the point of a center punch with slag remaining in areas you cannot reach with the chipping hammer. Tap the flat end of the punch with a hammer to break out the slag.
Run a wire brush over the weld to remove large loose particles of slag from the weld bead.
Wipe over the weld bead with a clean paint brush to remove smaller particles of slag and any dust covering the weld.
