Workshop notes / A closer look
A little weld before the long one.
Tack welds hold parts in position before final welding. They help preserve alignment and the required joint gap while the assembly is being made.
One corner. Three stages.
Select a stage to see what changes.
Get the position right.
Arrange and support the parts to the drawing. Clamps help keep them steady; the joint still needs to be checked.
LOOK CLOSER / The top seam has no weld metal yet.
Hold it. Then check it.
Short welds hold the fit-up. Recheck alignment, dimensions and the tacks themselves before continuing.
LOOK CLOSER / Short beads, with bare seam between.
Continue with the weld.
Complete the required welds using the specified procedure and sequence. Tack welding helps control movement; it does not eliminate distortion.
LOOK CLOSER / Only the top-face weld is shown completed here.
AI-generated concept images. Tack size, count and spacing are illustrative—not a welding specification.
So, are more tacks always better?
No universal count fits every job. Size, spacing and location depend on the material, joint and welding requirements.
Can a poor tack just be welded over?
Small does not mean unimportant. Defective tacks can compromise the final weld; address them according to the applicable procedure.
Technical reading: TWI — What is a tack weld?
