How do I prevent warping when welding thin sheet metal?
Documented on the Ford Mustang build
Published February 26, 2026
Use short tack or stitch welds spaced apart, allow cooling between welds, grind minimal material, and clamp panels from the underside.
Full Answer
Use short tack or stitch welds spaced apart, allow cooling between welds, grind minimal material, and clamp panels from the underside. Back-purging and using proper heat settings help reduce distortion.
Documented In This Build
Related Knowledge
What wheel/tire sizes can this modification accommodate?Do I need to weld the new fender wells, or can I rivet/bolt them?Will modifying the inner fender affect vehicle safety or inspection?How do I protect the repaired area from rust and road debris?How much extra tire/wheel clearance can I expect?How difficult is this for someone with limited metalworking experience?How much wheel/tire clearance should I leave when shaping the fender well?How long does a project like this typically take?
Related Parts
Sheet metal (mild steel) - 18-20 gauge
$50
Universal inner fender liner / splash shield
$30
Seam sealer (automotive)
$10
Pop rivets / sheet metal screws
$5
MIG welding wire / shielding gas (consumables)
$20
Body filler (Bondo or similar)
$12
Primer and paint (rattle cans or small kit)
$40
Related Tools
Measuring tape and marker
Angle grinder with cutting and flap discs
MIG welder
Reciprocating saw / metal cutting saw
Drill and spot weld cutter / drill bits
Hammer and dolly set
Clamps (C-clamps / locking pliers)
Body sanding blocks / orbital sander
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