Fusion (arc) spot weld
Applied to joint
Overlapping sheets — spot welds at interface
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Description
A spot weld made using an arc welding process (typically MIG/MAG or TIG) rather than resistance welding. The arc melts through the top sheet and fuses into the bottom sheet, forming a spot-shaped weld. Only requires access from one side.
In plain English
An arc spot weld -- you hold the MIG or TIG torch in one place, burn through the top sheet, and fuse into the bottom sheet. Unlike resistance spot welding, you only need access from one side and you do not need special electrode equipment. The weld looks like a little crater or rosette on top. Commonly used in sheet metal fabrication, particularly automotive repair, where you cannot get resistance welding electrodes on both sides. The symbol is a circle with a filled/shaded section.
Symbol position
Circle with shading on the reference line. Arrow side indicates the accessible side.
Size notation
Weld diameter 'd' to the left. Pitch if in a pattern.
Common uses
- Automotive body repair (MIG spot welding)
- Sheet metal fabrication with single-side access
- Attachment of thin sheets to thicker members
- Replacement for plug welds in thin sheet applications
