Definition
A type of weld in which a narrow line of molten filler metal is laid down on the surface of a base metal, or along a joint, without significant penetration or weaving. Bead welds are typically used to build up a worn surface, fill small grooves, or join thin sections of metal in aircraft structural and repair work.
Plain English
A thin, rounded line of welded metal laid down in a single pass, looking like a small raised bead running along the surface or seam.
Context Anchor
Seen in aircraft maintenance, especially when inspecting welded tube structures, engine mounts, brackets, and repair work.
Derivation
The word 'bead' comes from the Old English 'gebed' meaning 'prayer,' originally referring to small round prayer beads on a string. Over time it came to describe any small, rounded shape. In welding, it describes the rounded, bead-like ridge of solidified metal left behind by the torch or arc.
Why Pilots Care
Pilots and owners inspecting welded structures, such as steel tube fuselages or engine mounts, should recognize the appearance of a proper bead weld. Cracks, porosity, or irregularities in a bead weld can indicate a structural defect that requires inspection by a qualified mechanic before further flight.
Intuition Check
Do not think of bead welds as separate little beads attached to the metal. In this context, a bead is the raised line of metal formed by the weld itself.
Example Sentence 1
The mechanic ran a clean bead weld along the cracked engine mount tube before painting and reinstalling it.
Example Sentence 2
After completing the repair, the technician laid two even bead welds to restore the spar cap strength.